How do i get rid of this virus or whatever it is. I got it the other dayt and my computer is now mes

I accidentaly downloaded somthing i didnt want to, my antivirus caught it but i slipt and told it to do no action against it. Now every time i try to open any program on my computer, it tries to open it with windows media player. I thought i would just empty out the computer and reinstall everything but i can even do that. When i go to open up the admininstrator profile , it tries to open it up with WMP. Some programs will run if i open them as "run as" , but my antivirus picks up nothing and i cannot download any other antivirus because it will try to run it with WMP. I think it said it was a trojan but im not sure. Can anyone help me?

How do i get rid of this virus or whatever it is. I got it the other dayt and my computer is now messing up?bmw

Try some of these:

Spyware, Adware, Trojans, Malware, Dialers, Keyloggers, Popups:

http://www.download.com/Ad-Aware-SE-Pers...

http://www.ewido.net/en/download/

http://www.javacoolsoftware.com/spywareb...

http://www.download.com/Bazooka-Adware-a...

http://www.javacoolsoftware.com/sgdownlo...

http://www.safer-networking.org/

http://www.download.com/HijackThis/3000-...

http://www.emsisoft.com/en/software/down...

Online Scanners:

http://www.webroot.com/consumer/products...

http://www3.ca.com/securityadvisor/virus...