virus attack...?

So I was about to watch...Hannah Montana the movie on a movie website, and I did this before, same link and everything, no problem.
But then, of course, a message comes up saying that a virus has been detected, and you should install a software. Wondering if I should do it, I said yes then quickly exited out.
I tried to get a decent anti-virus, but the installer doesen't work.(AVG)
There doesen't seem to be anything wrong, but I want to get a good free anti-virus and make sure. What is the best?

You've already tried it. I suggest... what was the name?
...
It slips my mind for the time being. It's a Windows trojan-detection software (It also detects browser cookies), and if what you got isn't too bad, it'll fix it. Otherwise I suggest AVG or Avast!.

Avast!: http://www.avast.com/

And AVG you've already tried. I have a little experience with viruses (bad), so I can tell you this: If you ever get anything REALLY nasty, ask CK. He gots a link to the BEST site ever. But I gotta tell you, it's not for your everyday "run-of-the-mill" virus. So it doesn't help you much here. Just for future reference.

My computer does not meet the system requirements for avast.
I found one called kaspersky, I think it might work.

edit: Okay this is just stupid. All the ones I tried don't support windows server 2003.

The thing is, my step cousin got a virus twice from that site in the last week and they had to start the computer from scratch because it wouldn't start back up. There's a difference though. On her's a message on the bottom right pooped up saying "your computer is infected" every so often before.

edit2: Well, I restarted the computer, and it was completely normal. No errors or anything. I'm starting to doubt the virus is there...unless it is so tiny the computer or website thing barely noticed it.
So, I know it might not be much, but I want to get rid of it quick just in case it grew and I had to redo the laptop.

Yeah... Windows Server 2003... Do you live in the past?

and what exactly were you doing watching movies illegally online not expecting to maybe be viruseded? (and hannah montana? o.o )

yeah... I just felt like it.
I don't know why I never updated to a better windows... I might soon anyway. Even though I really don't think the virus is really there... NOTHING has gone wrong yet.

backup your files in case so that you can put it back easily instead of losing it or having to wait for the internets to download it for days again :3

Try this:

http://onecare.live.com/site/en-us/default.htm

Scan with that; it might not get everything, but it should hurt the virus enough for you to clean up the rest with a quick scan on Avast or AVG. Used that method on both my mom's and sister's computers.