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I have with me a machine with Windows XP. It starts, but after a few moment, it will restart itself again.

I tried booting via safe mode, and other options but to no avail. It always stops on mup.sys file and resets itself.

Is there a way to boot up the PC, run a scan disk to check the hard disk? I have with me a Knoppix CD. Does Knoppix contain some utility to scan the hard disk?

I cannot format my hard disk because of some important documents I have inside. I want to save/backup those first before doing a reformat.

I can't seem to locate my old Windows XP CD. If you still have your CD key and lost your Windows XP CD, where would one be able to download the installer?

@Col - ntfsfix only fixes the NTFS problem, but it does not do a scan disk type of checking. I want to check the hard disk the same way that scan disk does it.

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migrated from Aug 27 '09 at 13:43

This question came from our site for system and network administrators.

Check in the BIOS to be sure that the "Restart on BSOD" (or whatever your manufacturer calls it) option is off. – EBGreen Aug 27 '09 at 13:44
What's the make of your machine. @ebgreen That's a setting inside windows not the BIOS so he won't be able to get to it. – Col Aug 27 '09 at 14:11
Ooops...brain fart. – EBGreen Aug 27 '09 at 14:14

Try doing ntfsfix from the knoppix CD

If your laptop has a bios option for checking the hard drive I'd try that in case it's a hardware issue as well.

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There appears to be a lot of chatter about this problem.

I know posting links is bad (I hate it) but this post titled How to fix an XP\Win 2000 System that freezes after loading mup.sys while booting has background information and numerous fixes that you can try.

I also read a random fix which involved try to boot up without the mouse a couple of times, so maybe that would be a good thing to try if you do not have an XP CD to hand.

Reports of failed disks, bad memory, corrupt mup.sys file, bad internal/external USB hub, so many different causes. You could try removing sticks of memory, one at a time and try to boot without any USB devices attached.

Best solution would be to grab an XP CD and do a chkdsk /f, system restore (via recovery console if you still can't get into Windows) and/or a repair installation.

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Just had a user drop by with a laptop in this state. He had a couple of viruses on the box. Best bet is probably to format and reinstall. If you still have your installation key, feel free to borrow/copy some media from a friend (make sure the version matches, OEM if it was loaded on the box when you got it - retail if you bought the box, etc.).

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@Jeffrey It's usually on a sticker on the bottom of the laptop :) – Col Aug 27 '09 at 13:48

The easiest way to fix this is to use the Windows XP cd.

First things first, try pressing f8 after the BIOS has finished but before the Windows flag/logo has appeared and do disable restart on system failure.

When you boot now, make sure it is mup.sys that it is failing on.

Next, put in the XP cd and go to recovery console and try to copy this file from the cd to your hard drive (may need extracting).

But, if you want a quick recovery, the best thing to do is to reinstall windows over the top - preserving all your files and then you can copy them off, just be sure not to format your hard drive during setup.

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