First things first. Download malware bytes.
Malware Bytes:
Malwarebytes : Free anti-malware, anti-virus and spyware removal download
Malware Byes is a great anti-malware software that has saved me noumorous times with viruses. I STRONGLY recommend it.

Originally Posted by
Alen
First and foremost, don't use two AVs that could clash. So don't use Malwarebytes' AV and another one, especially if both have real time protection and the likes.
Try an anti-virus.
I know, they may not always help, but it helps if you don't really know what your doing. If your think your work with really xpirienced coders, chances are its FUD, and an anti virus cant take it down.
You can find some free keys, or some other creative way of pirating it.
Scan all your programs with online scanners. (Jotti, Virus Total)
When you download something, try to scan it, or find virus scans for it, this will prevent the virus before it happens.
Post some of your ways you prevent viruses and such.
ONE LAST THING.
Dont be an idiot, and don't download everything you see.