Once again, this belongs in computer security board...
Ok if you can't install any Anti-Virus programs, then I recommend you download and save the installers on another computer and burn them to a CD or put them on a flash drive. Then, boot your computer into safe mode. (Tap F8 repeatedly during boot to launch into boot menu.) Install your anti-virus software now. You should be able to do this in safe mode. Once installed, run full system scans and delete what it tells you is there.
I recommend AVG Free and MalwareBytes, later once your computer is restored, download Spybot Search and Destroy.