Catastrophic problems after initial boot-time scan

In attempting to help an elderly woman with computer issues on her XP system(without a speck of security software installed, I found it infected with numerous spyware, trojans, etc. I managed to get it online, despite dozens of attempts by various malware to hijack my connection. I installed Avast 4.8 Home and restarted.
During the first boot-time scan it identified loads of infected files, some of which were in system/windows files, which I had “Move all to chest”. A few were not movable, Avast indicating they were “Read-Only”, which I said “ignore”.
Once it finished and Windows started, I still have some pseudo-pop-up window that says windows is infected, but I suspect that is either a main or side effect of something still in the system. The huge problem is no, desktop icons, no toolbar/taskbar/start menu (possibly Explorer not starting?) and therefore can’t further diagnose anything. When I restarted in Safe Mode, I can’t do a System Restore and Avast says it “can’t initialize chest” so no files to restore, and trying to open Task Manager freezes the computer.

Sorry for being so wordy- I’m trying to provide as much info as I can, so someone can tell me what to do- I’m lost!
Thanks in advance,
deeyan

others can answer this better than I from west coast US
Some of our European Members should be online soon

I gave up- gave the old lady back her computer, since I had got to the end of the line, and found no help here.
Shoulda, coulda, woulda, eh?

With a computer so badly infected, your best bet is to back up the data, reinstall the OS, download the latest updates and install an AV. You can spend hours trying to clean such a computer but in the end, even if you get rid of all the infections, there are likely to be problems as a result of the malware (stabilty, function of OS & programs) which the computer owner will blame you for.

deeyan, I have the same opinion of Frank… it neither you nor your friend are computer savvy, maybe consider backing up the data, start again correctly (with an antivirus and protected).