First and foremost, thanks everyone for responding to my post. I would like to think that I am not completely brain dead when it comes to the hardware side of PC gaming but... I took apart my PC and gave it another thorough cleaning. Sure enough, I had completely missed the caked on dust and debris that was covering the heat sink on the CPU. It was so bad the surface appeared to be smooth metal etc. After blasting it thoroughly with compressed air, I rebooted my rig and yep, it has not crashed since. I guess the answer to some problems can be very unbelievably simple. I may still replace the mother board and CPU with an upgrade but there is no hurry.
Thanks again.