Diagonal lines on screen, MacBook Pro won't start.

Hello!

My MacBook Pro, which I bought back in 2007, has been acting wierd lately. Suddently it started displaying discolored rectangles in a diagonal pattern across the screen and it froze. I shut it down by holding down the power button because nothing else worked, keyboard and mouse was not responding. When I restarted it it displayed the lines again and froze displaying a completely gray screen, not booting up. Tried to reboot again several times with the same result. Won't start up using the install disc either. I was then able to start up in Safe Mode and was able to backup my data. I have been trying to reinstall the OS but the process stops at different points again displaying the lines...

To give you an idea of what I'm talking about take a look at the picture below...

Guess I want to know if this can be fixed without having to send it to the doctor... :-(

Thanks!