Reading the nice bit in red above every post...
Note: If you're asking for technical help, please be sure to include all your system info
Without knowing some specifics, it's impossible to answer your question. It's like taking your car in and only telling the mechanics it's making a funny noise, expecting them to instantly diagnose the problem. It could be a belt issue, could be a lack of lubrication issue, could be some misc debris caught up in something, etc.
im using a winXP sp2...im not contented on my computer's speed...it slows down whenever an application is closed???what to do??