MacBookPro stopped booting what should I try?
If this is an early 2008 Macbook pro (4,1) then you may finally have encounted the infamous horrible Nvidia 8600 hardwarelproblem that everyone with this model is waiting for.

Nvidia problems

Possibly affected systems include 17-inch, 2.4GHz MacBook Pros, 15-inch, 2.4 and 2.2GHz MacBook Pros, and MacBook Pros manufactured in early 2008, all with Nvidia GeForce 8600M GT graphics chips. All such systems were made between May 2007 and September 2008.Macworld | Apple offers MacBook Pro Nvidia graphics repair

MacBook Pro: Distorted video or no video issues