Should be able to upgrade to a Pentium Dual Core or a Core 2 Duo. But seriously dude don't bother it's not like a walk in the park to upgrade CPU on a laptop like it is one a desktop. My advice. Sell it, put some more money buy a new nice laptop for $400-$500 already with a better processor and W7. On top of that this model could potentialy have the faulty Nvidia graphics. Meaning tomorrow you decide to upgrade the CPU, two months later board dies on it. You're then how they say...SOL.