Log on failure loop after avast! boot scan

Hello. I posted a problem yesterday, but a combination of my own ignorance and the fact that I'm on the other side of the globe led to a lack of help; thus, I post again, hopefully early enough and lucidly enough to receive some suggestions. And thanks in advance. Problem with XP Home SP3: in the course of updating my ATI Radeon Xpress 200 driver my avast! Home Edition went crazy with a warning that components of the update were tainted by a win32:vitro infection. After checking the containing folder with both Malwarebytes' and SUPERAntiSpyware, each freshly updated, and having clean results, I decided to continue with the update installation, telling avast! to ignore each of it's 7 to 10 warnings. Installation successful, reboot. Upon start up avast! again went haywire, warning of a win32:vitro infection multiple times. After the third or fourth warning it asked if I wanted to do a boot scan. I said yes. At the one-third mark of the avast! boot scan it paused and asked of 7 or 8 items in a group, and I clicked on delete. At about the halfway mark of the scan it asked about a series of 3 or 4 items, and eventually I clicked 'yes to all.' Finally, at about the three-quarters mark the scan suddenly stopped and the computer changed to the orange Compaq screen with a single window in the middle with the title bar 'Log On to Windows', and lines saying 'User name: Administrator' and 'Password: [blank]'. I've never seen this window (I'm the comps only owner) or set a password. When I hit 'enter' with a blank password I get a five second loop from this window to 'Loading your personal settings' to 'Saving your settings' to 'Logging off' and back to the original window requesting a password. If I shutdown, then restart, everything begins normally: black screen with press F10 or esc in the bottom, left corner morphs into main Windows XP logo screen to the two-tone blue Windows screen and my PageDefrag running normally to orange Compaq screen, but then up pops the window requesting a (non-existent as far as I can figure) password. When I boot and go to Advanced Menu Options, every single option--Safe Mode, Safe Mode Plus, Other Safe Mode Plus, etc.--yields the same result: a 5 second loop as described above. Also, my (blank) screen saver kicks in properly at the 3 minute mark. I borrowed a friend's XP Pro CD and used the Recovery Console. Multiple runnings of chkdsk /p and chkdsk /r, until neither reports an error, have done nothing. It seems obvious to me that during the boot scan I deleted something required by windows to access the OS. I'm thinking that using the Recovery Console to run both fixboot and fixmbr would be my next step, and if those fail then perhaps doing a System Restore with the Recovery Console. Please, if anybody has an idea, hopefully based on experience, I'd be very very obliged. Thank you for your time, and it's 07h24 here, southern Thailand, so I'll be awake for a long time .

Ahhh, would it be possible to do a repair install in the recovery console using my friend's XP Pro CD? And, my computer is a Compaq/HP with a recovery partition. Is it possible, does anyone know, to do an xp repair installation using the recovery partition? Thanks.

Boot into the Recovery Console and type these three commands one after the other:

cd system32
copy userinit.exe wsaupdater.exe
exit

Many thanks for your help. Does it matter that the Recovery Console I'm using is from an XP Pro CD but my OS is XP Home? Also, should I assume this is to be done in my main C:, and not the recovery partition D:? Thanks for your patience . Also, will there still be hope to recover my data? Sorry for my ignorance.

It won't matter that it is an XP Pro CD.

Yes, it should be done in the C: drive.

Hopefully we will get your data back.

Loaded the disk while awaiting your reply; will run now. Thanks again, and great signiture .

'The system cannot find the file specified.' . Shall I still run 'exit'?

Run these commands instead (where d: is the CD drive).

d:
cd i386
expand userinit.ex_ c:\windows\system32
exit

D: is my Compaq recovery partition; E: is my CD drive. Shall I use E:? Sorry for my paranoia.

Yes, use e:

e:
cd i386
expand userinit.ex_ c:\windows\system32
exit

The first 2 commands went fine, but the third one resulted in 'Access is denied.'

If you are infected with virut, and I think you are, there's no way to fix this. You would have to run windows as a repair disk and then all your executables in installed programs might still be infected.

Try it like this:

expand e:\i386\userinit.ex_ c:\windows\system32

Depressing thought, but can I still make the best of it and recover my data (20 gigs of music in folders on my desktop is really all I care about)? Any use for the recovery partition? And, supposedly no questions are stupid, but do I have to refresh my page every 30 seconds to see replies?

Sorry, saw DaChew's message first. Budapest, your last suggestion resulted in the same 'Access is denied' message.

Maybe this will work:

expand c:\windows\servicepacks\i386\userinit.ex_ c:\windows\system32