My fastfat.sys file has been corrupted and now my machine wont boot. I try a repair using the WinXp cdrom and I get an error "code 4". There is no way for me to repair or reinstall windows Xp using the boot disks or even a regular boot disk. Any ideas on wht to do next? HELP!

if you're getting to a c promt type "format c:" after the promt. this should do the reformat. after the reformat is complete, just pop in your xp cdrom and reinstall. hope this helps! B.

OMG....I had that same problem. You have to copy fastfat.sys back to the directory. Luckily I have 2 computers, both with XP. THe one that was corrupted was with the retail winXP, I used the fastfat.sys file from RC1 of XP. You have to use a win98 boot disk or something, so you can get to a command prompt. C:\windows\system32\drivers\fastfat.sys is the directory where you can find the file in DOS, you'd want to type in c: cd \windows\system32\drivers\ g: cd \windows\system32\drivers\ xcopy fastfat.sys C: /h /r c: attrib -r fastfat.sys I'll explain what this will do... First it will change to your C drive, then change to the directory \windows\system32\drivers\. Windows will remember this path for the copy command. Then it will switch to your G drive, assuming that is where the file you want to copy is stored, and then again changing the path for the drive. XCOPY is basically the same as copy, but it has more features. Because we changed the directories on both drives, we only have to mention the filename and target drive. The /h parameter allows you to copy hidden and system files, which might be the case, and the /r parameter allows XCOPY to overwrite read-only files. Finally, the ATTRIB command removes the read-only flag which the file would have, since it's copied from a CD (all files on a CD are treated as read-only by nature of the media). but now, after all that, I got the file to sucessfully copy, and I no longer get that error, but windows freezes during bootup. And I still get error code 4 when I try to reinstall windows using the CD. I'd do a reformat like Brandy suggessted, but then I'd lose all my data!! which is what I'm trying to save, otherwise I would not hesitate to reformate...