Flash Crashes? Possible Virus?

Okay, this is really annoying me. I tried starting up Mozilla, and when I loaded Xat, something went wrong with the flash and it crashed. I tried refreshing and Mozilla just stopped working. I tried using Chrome, but whenever I try to do something flash related, such as Youtube or Xat, then I get an Error Message about a plugin called Shockwave Flash has crashed. Something like that. Something is definitely wrong. Also, I have Facebook Chat and Aim connected, and whenever I try to talk to someone, that crashes too. I think I have a Virus