Macbook Pro and Zig Zag Lines

Hello....I am wondering if anyone can shine some light on my problem. I have a Macbook Pro (15", Intel Core 2 Duo, 2.33 GHz) that is about 4 years old.

About 2 years back the MBP tossed up zig zag lines across the screen and refused to work. I put the MBP away for a year and 1/2 and on a whim decided to hook it up to my mini to see if I could recover my data in target mode via firewire.....I could, and tossed my stuff on to my ex-hd. I then tried running Disk Utility on the MBP via the Mini. Once finished repairing the disc I restarted the MBP and it worked! The MBP has worked since early Spring and craps out every other week or so...back to the zig zag lines, etc. I repeat the above mentioned first aid and it then works again....(I'm unable to use the MBP's Dick Utility because it quits before it can open???)

I was told it could be the logic board...and the MBP does run hot...I just find it interesting that I can hook it to the Mini for some CPR and it works again!

So there you have it.

Any takers?

Thanx!