Computer infected with malware? help!!!?

[Nahum]

The download may have been cancelled, but what caused it in the first place?

Perhaps you just visited a bad site. Worse, you might have some hidden malware or browser plugin that initiated the download, and is waiting for another opportunity when you aren't paying as much attention.

Definitely give your computer a thorough scan in Safe Mode with antivirus and antimalware software. Microsoft's own Security Essentials is a pretty good antivirus program for being free. Malwarebytes has a good antimalware scanner, while Spybot Search & Destroy has an "Immunization" feature that can prevent your browsers from wandering into trouble.

You can also use programs such as Autoruns or HijackThis to see what programs are set to self-start, research suspicious entries, and remove those that don't belong.