I am Running This On MY Computer: intel pentium 4 1.8ghz,512ddrRAm,Gforce 5500fx, my average fps is around 50 the highest is about 90, lowest is 28-29.I just thought that my fps should be able to stay higher then at least 40 fps on every map, but it doesnt. if anyone could tell me a way to fix this it would be appreciated.

also i was wondering if a virus or spyware mite be able to lower my fps?

Type in the console "com_maxfps1000" w/o the quotes. If that doesnt work try putting a space between "maxfps" and "1000". Hope this helps.