Win7 64 bit BSOD on startup

[stuck]

stuckling2's Acer 5750G laptop was fine yesterday. He thinks it installed a Windows update when he shut it down last night but he's not sure. Today on power up the BSOD flashes very quickly on the screen and then we get a Windows Error Recovery screen saying a recent hardware or software change might be the cause and giving two options.

The second option is just start normally, that's no good. The first option is Launch Startup Repair but as yet we've not found any option in there that will get the laptop to boot, more on this further down.

If we tap F8 during boot and then try safe mode the system stops and reboots when it reaches a file called classPNP.sys.

Going back to the Startup Repair... This gives a low res GUI that tells us Startup repair cannot repair this computer automatically. The problem details might mean something to MS but they aren't very helpful:
Problem Signature 01 6.1.7600.16385
Problem Signature 02 6.1.7600.16385 (these two lines look like OS versions)
Prob..... 03 unknown
..... 04 21200035
05 AutoFailover
06 9 (this line increments every time the repair tool is run so it's just a counter)
07 NoRootCause
OS Version 6.1.7601.2.1.0.256.1
LocaleID 1033

Dismissing that allows you to get to 'advanced options' one of which is to roll back to a system restore point but although we can see a list of restore points we can't select any of them, they all say you must enable system protection for this drive.

Umm, I'm stuck.

Ken

[stuck]

Been Googling and learnt that Win 7 safe mode stopping at classpsnp.sys is a known issue. I've tried two 'fixes' so far:
1) At a command prompt rename class.psnp.sys to classpnp.old. Curious thing here is that the command prompt is for X: I can't get to C:
2) In the BIOS change the SATA mode from AHCI to IDE (the actual fix was to choose 'compatibility' mode but that option is available on this laptop but someone else said choosing IDE worked for them.
NEITHER of these work.

Ken

[jonwallace]

Been Googling and learnt that Win 7 safe mode stopping at classpsnp.sys is a known issue. I've tried two 'fixes' so far:
1) At a command prompt rename class.psnp.sys to classpnp.old. Curious thing here is that the command prompt is for X: I can't get to C:
2) In the BIOS change the SATA mode from AHCI to IDE (the actual fix was to choose 'compatibility' mode but that option is available on this laptop but someone else said choosing IDE worked for them.
NEITHER of these work.

I take it that you managed to rename the file. (if not, then try booting from http://www.ubcd4win.com" onclick="window.open(this.href);return false;)
When I search my HD I find two copies of classpnp.sys, both with the same date/size. One is in "C:\Windows\System32\drivers" and the other is in the wonderfully named
"C:\Windows\winsxs\amd64_microsoft-windows-classpnp_31bf3856ad364e35_6.1.7601.17514_none_73a9340ac2b15f83"

I think you would have to rename both to disable it.

At the end of the day there's always the "take off and nuke it from orbit" option. Or less drastically, http://windowssecrets.com/top-story/win ... reinstall/" onclick="window.open(this.href);return false;

[stuck]

Thanks Jon,

I did rename the file, at least I think I did since the rename command didn't give an error. Yes, I discovered about the second copy in the wonderfully named folder in the course of my Googling and yes I think I renamed that one as well since again the rename command gave no error. However, I didn't do both renames at the same time so that's another variation to try. Mind you, both the sticker on the laptop and (when you could get at it) the Control Panel System Properties dialog say the CPU in this machine is an Intel one not an AMD, as suggested by the ...\amd64_micrisoft-windows-classpnp... folder name.

Another possibility, based on what I've read and what I note above about only being able to 'see' an X: drive and not reach C:, is that the problem could be with the HDD (unmountable volume). My plan for tonight is to remove the HDD and connect it to another PC, as a slave, to see if I can browse the drive at all.

The nondestructive reinstall option requires a Win7 DVD, I don't have one, the laptop didn't come with one. I might be able to borrow one though but as the laptop is only a couple of months old I will be seeking redress from the retailer before I go for that or the nuclear option.

Ken

[jonwallace]

Ken,

I think the "amd64" bit refers to the 64 bit instruction set rather than an AMD processor.
Windows 7 is available to download as an ISO file (officially!), all you need is a license key (like the one on the bottom of your laptop) and maybe not even that for a reinstall.
Look here http://www.w7forums.com/official-window ... 12325.html" onclick="window.open(this.href);return false;

[stuck]

Can't comment on MS using 'amd64' mean just 64bit vs 64bit for AMD. The laptop is a 64 bit machine. Presumably if I Googled enough I might get an explanation.

Oh good, I'll look into getting a copy of that ISO.

Meanwhile, I phoned the retailer. They reckon the problem is with the HDD and said one of two things can be done, full return or, if I'm up to it, sending a new HDD for me to swap with the original. I'm happy to fit a replacement HDD but the catch is I have to phone Acer, so the actual decision on full return vs being sent a new HDD probably won't be down to me.

I'll report back on progress in due course.

Ken

[StuartR]

Good luck.

I will be interested to hear about the overall customer service experience, as well as the outcome.

[jonwallace]

http://www.cpu-world.com/Glossary/A/AMD ... ology.html" onclick="window.open(this.href);return false;

Remember that the ISO is for a DVD and is HUUUGGGEEE. (Don't try to download it on dialup )

[stuck]

Phoned the Acer, unsurprisingly they aren't interested in shipping out a new HDD. They won't do anything until I've first tried a factory reset. They did say the warranty would not be void by me removing the HDD and slaving it to another PC to recover the data on it. They were very polite and although the voice had a strong non UK accent it was perfectly understandable.

Phoned the retailer back. They'll only take it back if the HDD is physically faulty.

So, I removed the HDD and hooked it to my XPMCE box, where it appeared as a couple of new drive letters. Got the data off, it all seems fine.

Searched the HDD for classpnp and found two copies, in the folders Jon gives above. Neither could be renamed, access denied. Downloaded unlocker and tried that. It allowed me to rename the copy in the \system32\drivers folder but it couldn't rename the one in the folder with the huuuuge long name, the error was that I can't specify a different path or folder when renaming. I was offered the option to rename on next boot so I restarted but the file didn't rename.

Put the HDD back in the laptop and tried to boot to safe mode. It failed at drive.sys this time.

Time to stop for tonight. Tomorrow evening I go for the factory reset.

Ken

[Bigaldoc]

Happy at least that you got his data copied. Good luck tomorrow !!!

[stuck]

Good luck tomorrow !!!

It's the day after tomorrow but who's counting? I didn't go for the factory reset last night because a helpful person offered to lend me his Win 7 master DVD so I could try an in-place reinstall as suggested by Jon further up this thread.

He brought the disk to me this morning but it turns out it's a straight Win 7 disk, it doesn't include SP1. Fred Langa's instructions on doing an in-place reinstall explicitly tell you you can only use a non SP1 master to fix an SP1 install if you first uninstall SP1. I can't do that as I can't boot the laptop at all.

Soooo, Plan B (or is it C/D/E/?) is to build my own SP1 master DVD (and/or a master USB disk) using an iso from the link in Jon's post and try that.

The nuclear option remains a last resort because one of the apps that will get wiped by doing that won't re-install until I can convince the software company that I'm not trying to create a second working copy, I really, really, can't unregister the first install via the correct (in app, on-line) method because that installation doesn't exist any more.

I'll be in touch...

Ken

[Bigaldoc]

Software companies, in their zeal to prevent theft, sure do make it a pain in the (you-know-what) for honest people !!!

[stuck]

I've booted the laptop off a DVD containing a Win 7 SP1 64bit ISO. A small step forward.

Next hurdle is that on re-reading Fred Langa's article on a in-place reinstall it appears that Windows has to be running and I'm certainly not seeing the screens in his guide. The bootable USB gives two choices. Install or repair. The repair option takes me round the loop I get when the laptop fails to boot from its HDD, "can't repair".

I can use a command prompt to see that the classpnp file in the \drivers folder has been renamed and the one in the folder with the huge name isn't there at all.

It's not that late here but I am tired so I'm going to stop for the night. I think I'll try and copy the classpnp files off the install disk on to the HDD as the next step and see if that helps.

Ken

[stuck]

You can't do an in-place reinstall if Windows won't boot. That option requires you to be able to run setup.exe on the install disk from inside Windows. So that route was a non-starter.

I did eventually get CHKDSK to run from a command prompt accessed via the recovery console. First time it ran it reported something about 'bitmap errors', which it fixed (still wouldn't boot though). Second time through it took hours but reported bad sectors, not many but at that point I gave up.

I know you get bad sectors on disks but in all the years I've used PCs while they've ruined the occasional floppy disk they've never screwed up a HDD, e.g. stuckling1's Acer laptop has had heavy use and wear for years and never even given a hint of a bad sector. This machine is only just over 2 months old and it's dead in the water.

Yes, I suspect a factory reset will work around the bad sectors but having had the disk fail once and so soon I'll have a hard time trusting it again. I called the retailer again this morning. They have agreed to a return under warranty (free pick up). I will take a note of the HDD serial number before it goes back and point that out to the retailer. I don't want the same part back.

Ken

[stuck]

Don't think this will be the very last word on this saga but I am getting near the end.

The retailer has confirmed the item was faulty and have converted my returns ticket into a new order ticket. However, the item is out of stock. Given the speed at which laptop specs update my feeling is they won't be able to get an identical replacement for me so I'm expecting to have to listen to a lot more tinny music while hanging on the phone waiting to speak to someone (and then be passed on to someone else ). I reckon the outcome will be that I have to part with more money off me in order to get a 'better' / in stock model instead.

Ken

[stuck]

The final disappointment is that I can't get a comparable spec machine running Win 7 from this retailer.

I don't want to risk buying a Win 8 box because Avid (the company behind Sibelius) have told me , "I doubt we'll ever 'officially' support First version 6 on Windows 8 since there is an upgrade First version 7 available..."

I have got a full refund to my credit card instead and been busy looking for an alternative elsewhere. Trouble there is a lot to be said for the devil you know

While it has been a bitter disappointment to have this laptop go bad so soon the retailer have been good in the way they've dealt with it. Can't say Acer were that sympathetic though.

Ken