Macbook Pro constantly freezing

Macbook Pro 15" 2009 model, 2.53 ghz
Running Lion OS

For the past few days, my MBP has been constantly hard freezing. All of a sudden everything stops and I can't move my mouse cursor, forcing me to hard boot every time. I thought it might've been Google Chrome because I was able to keep it running fine while it was closed. When I switched to Firefox, it froze anyway (though it did take longer). Perhaps a browser thing? Chrome/Firefox are the only apps that are constantly running, with iTunes left open every other time. Any solutions? I must've done it more than 10 times today alone...

Side note: I also have a problem where my AirPort card goes out. What I understand that it's problem due to my screen hinge partially disconnecting. Maybe it's related to the freezing problem?

how much memory do you have? have you tired using any junk cleaning apps like macclense, cleanmymac, etc?

Update: Took my MBP to a Genius today. My hinge is damaged and since the antennae runs through it, it causes the AirPort card to go out. He also said that the hinge may be messing with some other component causing my MBP to freeze. He said to either have it replaced (costing $500) or use it as a desktop (connect to external monitor and keep MBP closed).