Hey all.I just want to ask about my pc.Will I be able to play crysis 2 without lag or crash on

Processor:Dual core E5700 3GHz

Video Card:Ati radeon 4350/4500series 1gb

I want to upgrade the ram to 4gb and change my windows xp to windows seven.Is it worth upgrade?Does it improve the performance?Please someone reply as I am about to upgrade my rig.