I'm sorry, but your computer is doomed.

...*sob*
This is why:
1: You CAN NOT DELETE IT. (because you told us that is just downloads itself again.)
2: You CAN NOT USE ANY APPS (because of virus)
3: You CAN maybe download an anti-virus agenst this, but if it dosen't work, then i sorry but you are DOOMED.
You better GET BACK-UP FLIES OF ALL YOUR STUFF ON DISC OR THUMBSTICKS BEFORE IT'S TOO LATE!
If you somehow counter ANY of these reasons, you CAN save your computer, but you should probably get back-up flies of you r files on to a type of storage not in your computer, first.