Sorry to hear of your problems yet again, Titia. Hope you can find the culprit.
And I did get the rest of the Dell system, everything that was shipped to them. First install went squirrely when I connected the cable modem prior to finalizing firewall/virus settings, and some bastid tried sneaking in. Windows Explorer has absolutely no business trying to access the internet. So. Yesterday, I cleared the partition, reinstalled, and things went fairly smoothly. All updated, patched, and scanned, and returned to owner this afternoon. Since she uses dialup, and I wasn't entirely certain what she wanted to do regarding an ISP (she was using Yahoo), I didn't install/setup any dialup accounts. Her husband can do that, I reckon.
And Buggy, see if you can get AVG installed and updated, change the test settings for complete scan to include all files, and run it to find, quarantine, and attempt cleansing of infested files. If worse comes to worse, if you have another harddrive, try backing up things you want to keep (if they ain't infested), and reformat/reinstall. I just did mine today, as I wanted to be certain that old drivers were wiped clean, since regular uninstalls tend to leave crap behind which likes to cause conflicts.