If the system is that bugered and infected perhaps it may be of help to simply reformat and reinstall Windows.

That aside, simply changing the jumper on the HDD to CS or Cable Select may be of help.

Other options of use may be at How to take ownership of a file or a folder in Windows XP.

Another possibility may be to access then run a non-destructive System Recovery. You may be able to navigate to System Recovery from pressing the Windows key (between the Ctrl and Alt keys.) But if you choose to perform any kind if Recovery, I would suggest doing this on the bad HHD while it is installed in it's own computer, just for the safety sake of your own computer.

In any case, after removing the bad HHD from your computer I would urge you to scan your system for viruses, spyware, etc. with updated definitions. If any trouble makers got onto your machine, the longer you wait the more trouble they may cause.

Charlie