I have a home built system in my office which has worked well for years. Recently i have been having problems with the power supply. When I shut the system down, pressing the power button only turns on the system 1 in 10 times. Usually after shutting down i would just have to fiddle with it until it would turn back on. then once it was on it ran perfectly. SO i decided to replace the power supply. I believe the original one was a 400w which came with the case years ago.
I had a newer PC which i no longer use so i decided to pull the power supply out of there and drop it into my office computer. the new power supply is a seasonic 500w i believe. So i dropped it into the office computer and it fired right up.
after a couple days though i noticed that running heavy tasks like video conversion would cause it to shut the system down (no reboot). now this happens consistently. Every time i try to convert a video with handbrake, at some point in the process it just shuts down.
So I am wondering if there is something wrong with the new power supply.
I thought maybe it was a problem with heat but i never had heat problems with the old power supply, and all the fans are spinning (CPU, vid card fan, case fan...)
so what do you think? could it be the power supply?
Sounds like a motherboard issue to me.
Have you inspected the capacitors on the office pc mobo?
Bad caps cause many problems and eventually the pc will no longer function.
Heat also may very well be an issue. http://www.alcpu.com/CoreTemp/
Apparently your cpu has dried up paste on it.
You need to apply new thermal paste to the cpu.
Sounds like a thorough case cleaning is in order.
Those temps are horrible and no doubt are causing shutdowns.