Ok the questions pretty obvious with this one, Soo I have really have no idea if it can be. I've only worked on Desktop PCs and it isn't really hard that much, you just gotta find that is compatible to your motherboard.

I have a pentium quadcore laptop, it's pretty slow, but it has a 4gb RAM which is actually solid for gaming. I can play CoD just ok at low res. But then i wanted something more, it has integrated graphics so its quite shit. It's slow at most modern games, so I'm stuck at retro ones. Even Saint Rows III fps drops like crazy. So I'm thinking if you could replace the processor of the laptop, any tech support people there can it be done?

You can but it has to be compatible with the mobo. Sort of like how you need to match cpu and mobo sockets. However a laptop mobo is a bit more picky. I wanted to upgrade my i5 to an i7 of the same gen, but the mobo would only support the default cores.

But you might be able to get away with a new mobo too?