Tell us about

1. The PSU. Let's hope it's a single rail with 500+ Watts.

2. "the sound also quits working within seconds" isn't much of a clue but did the machine's maker supply an install plan? I find many of these machines had no plan except to use what Microsoft supplied.

3. FORGET HEAT SENSORS. They can be off, misleading and more. After a few years most figure this out. Try this. NO COVER and point a fan at the machine. Better, longer running or no change? No change has me looking at the install plan. Better or longer till the crash has me checking power supply and re-doing heatsink compound and mounting.
Bob