Do not know if this is a video card problem or not...PLease Help?

This is something I have never encountered. I play WOW and have Steam. I have a NVIDIA 8500 GT video card. I went to log into WOW today and the game runs fine with 50+ fps but then after 5 minutes my fps goes own to 5 fps. This happens to whenever I start Steam. I have never had this problem concerning a game. Please help.|||Please do NOT click on the link provided by the first respondent. This is what McAfee Site Adviser says about the site:



"Reported Attack Site!



This web site at new-porn-tubeportal.com has been reported as an attack site and has been blocked based on your security preferences.



Attack sites try to install programs that steal private information, use your computer to attack others, or damage your system.



Some attack sites intentionally distribute harmful software, but many are compromised without the knowledge or permission of their owners."



I wonder why Jhgkjg S has no contacts at the moment!?