Thats a nasty bugger you've got there, it'll be in your prefetch files and in your registry, you'll not be able to get rid of it manually unless you know exactly what you are looking for.
If you can get programs to run on the other account you need a free piece of software called Malwarebytes.
It really is extremely good at tracking these things down. Only problem is these XPantivirus 2010 and all the varients of which, which it sounds like you have, are specifically designed to prevent the program running. However, once it is installed, if you change the mbam.exe file to mbam.scr you shoud be able to run it.
That is scanning for things right now. I think I got my anti-virus to actually "vault" the evil files. It took a few tries to get it to install and run but it's going.
I usually only get adware, which is real easy to get rid of, find the file through a scan and delete the folder titled "REHUygaUYH78954SDHGhgrhgs6".
This one I'm like "What the fuck is going on?" It's sick.