Ps2 keeps turning off

[redzero36]

My fat ps2 keeps turning off when ever I play any game. It first started when I was playing a backed up version of one of my games that I patched to change the voices and ESR patched so it would work. Im guessing it has to do with the laser because the area where it was crashing and turning off at on the backed up version, I was able to get slightly passed it with using the original disc. Then after that both of them would crash at the opening of the game. I even tried other games and those still crashed. Also since the fact that my ps2 is old and I just started using backed up games I guessing it is my laser since backed up games burn out your laser faster. Is there a way I can be 100% that it is my laser and not something else. Im pretty sure I can eliminate the over heating problem because when I opened it up to do the disc swap I cleaned it out. Is there a way I can test it out to make sure the other parts of my ps2 is working properly.

edit. umm so I guess it may not be my laser. I left it on and trying to import my save game and it shut down and had a flashing red light. so i guess its not my laser, maybe. any Ideas