How do i improve FPS

Dakiras: There's a number of things that could affect this. As previously suggested in the thread, the cheapest and (often) most effective upgrade you can make is to the memory. If that's not fixing the problem, you're best checking your processes and making sure nothing is running that shouldn't be, or seeing what is taking all your resources. It could be that a background process is being run when you start another program and then doesn't close down properly.
You also might want to consider some cleaning software (they're free) that can help tidy up your registry and temp files. I'd advise a level of caution with this, though, if you're unsure of what you're doing with it. :)
Last resort without springing for completely new hardware would be to reload Winodws and start from a fresh, clean installation.