Hmm...system appears clean now. My guess is that something got corrupted through the Prevx disinfection.

Go to the Run box on the Start Menu and type in:

sfc /scannow

This command will immediately start the Windows File Protection service to scan all protected files and verify their integrity, replacing any files with which it finds a problem.

i did what you said, but i don't think anything happened. a cmd prompt window popped up for a second and disappeared, and that's about all that happened...?

and, yes, i tried logging back into normal mode; it took me 10 minutes to log in and everything was still slow. i didn't stay logged in long enough to see if anything froze or crashed or to see if anymore pop-ups appeared as everything was far too slow. a very puzzling situation... your help thus far has been greatly appreciated, but, im afraid it's not over, yet, unfortunately.

When you typed in sfc/scannow-- you had your XP install disc in the drive?
What Chiaz pointed out was that some of the infection he just removed may have corrupted a system file or 2... which would mean the symptoms might be there-- even if the infection is not. The scan by Windows may fix the rest.

in safe mode, i tried it both with the disc in the drive and without, each a failed attempt.
although normal mode boot is extremely slow, i decided to show some patience and attempt to run the scan there and it actually worked, however, i've hit one snag. my install CD is that of Windows XP Pro + SP2. that is, it contains the actual operating system plus service pack 2. i started the scan without any cd in the drive, but then it prompted me to insert the sp2 cd. i inserted said cd and the scan started. then, about 2/3's of the way through the scan, it prompted me for the windows xp pro cd, saying the one i have in the drive is not it, even though it contains, along with sp2, the full win xp pro os. i'm at a loss as to what to do here to complete the scan. any help would be appreciated.

This is a Full retail disc? OEM ?
Or a 'slipstreamed' one you made (nothing illegal about it-- just curious)

slipstreamed

Had you used it to install before this? Sucessfully?
(Not meaning any insult to your abilities)
If you have your original intall disc-- and you get to that point in the scan-- you could try swapping discs. A pain-- but if it gets you back to square 1 -- worth it.