Macbook Pro 2007 Crashes I have a macbook pro 2007 . 4gb of ram 320gb. i bought this macbook off eBay over the summer. it came with leopard , 2 months later then i upgrade to snow leopard, then to mountain lion. i currently have mountain lion 10.8.2 . the screen is kind of flickers and i don't know if its the graphics card or its just the screen. but one day i was using my computer and all of sudden it just turns gray and the screen starts flickering and it just kept going. i don't think its the screen because this flickering shuts down my computer and kernel panics comes up . when you restart it the computer, the apple logo that comes up looks like it has spots on it but doesn't boot. it stays and it freezes and restarts my computer. what to do ?
It very well may be the graphics card in your MacBook Pro. Apparently during the manufacturing process (of this generation) too much thermal paste was applied to the heatsink on the GPU, thus cooking it. If this is the case for you, Apple might replace it or reimburse you for repair, if they are still doing this. 

A few good links:
http://support.apple.com/kb/HT4132?viewlocale=en_US&amp;locale=en_US
https://selfsolve.apple.com/agreementWarrantyDynamic.do