First of all, my thanks to the tech support guys who've helped me here
Now, my problem is non-malware related for once.
I've wanted to restore some basic system files. However, I don't have the install disks as I didn't install the software on this computer (distant cousin did). I found out that you can bypass this by running the computer from the winnt32.exe file, which is in i386. I've looked in both i386 folders that contain thousands of files and IT'S NOT THERE!
So, is there any way I can retrieve it somehow? (I need it to have autochk.exe again, besides other things... I accidentally deleted autochk, it seems.) I look at kellys-korner briefly but nothing there that could solve the problem.