Having a kinda weird problem

i have win xp pro.dx 9.0 amd 2100 512 ram 80 gb maxtor hd gf 4600 vc.ive defragged and run disk fixer.for some reason the last couple of days everything has been getting really slow.during my games and just sufring using different programs.my fps in my games has gone down really bad,from like 90-30 ,but it doesnt happen untill i play for awhile.it doesnt start out that way at first just after say 15 mintues.my temp on my cpu are in the 50 -60 range.like when im surfing or doing other things the programs are slow to come up,then they all pop up eventually.im on cable connection that mostly good,but i can tell the difference between lag and something else.im leaving something out but if any one has a general ideas to try please post.thanks

 

try this...

http://www.windows-help.net/WindowsXP/tune-18.html