Since you'll need a more powerful CPU, you'll also need a new motherboard and RAM. Likely a new GPU as well. I believe you'd be better off buying a new PC with something like an I5 processor.
`
Good luck.
i am looking to upgrade my computer so i can play most games with no issues which i cant do at the moment if i give my pc details can someone have a look and tell me what would be a good updates to what i have.
i have a
HP G5200uk
AMD anthlon II x2 220 processor GHz
installed RAM 3gb 2.75gb usable
64bit op system
GeForce 6150SE nForce 430 graphics card
thanks to anybod who takes the time to help me out.
thanks stuart

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic