I do thank you for your attempts at help. I tried all you suggested long before I came here for help. It is now formatted and fixed. Don't guess I'll ever know what caused the problem which is kind of frustrating and sad, only cause I can't help someone else who has the same problem. You guys are all great!!!!

Thanks for the thanks Doc. We're glad the problem is fixed now. Sorry we didnt have the solution for you.

As I posted in a new thread on this subject (see http://www.d-a-l.com/help/showthread...90#post106690), I successfully resolved this problem by checking ALL "run" keys for invalid entries. In the past month, I've encountered not one but two examples of the "System32 folder pop-up on startup" problem and in both cases a blank entry in the RUN key for EXPLORER was to blame:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curr entVersion\policies\explorer\run
Name = wininet.dll
Type = REG_SZ
Data = [single blank]

In both examples, the problem arose AFTER disinfecting the PC's of multiple viruses. While that might appear to implicate the Zlob trojan (known to infect wininet.dll), it could just as well implicate one of the plethora of antivirus utilities I used to get rid of it.

I intend to monitor the disinfection process more carefully from now on.

P.S.: The blank in "CurrentVersion" must be from a glitch in the post software, it was not in my submission.