30 SECONDS AND SHUTS OFF

I have an HP 754N running XP. After not using for about 6 months I hooked up and started. It starts and runs about 30 seconds and shuts off. If I try to start it runs maybe 10 seconds and shuts down. 3rd try runs 1 second. If I wait 10 or 15 seconds it's back to the 30 seconds. I replaced power supply, no change. I tried different HD same problem. I'm at a loss. What is left? I have a newer Gateway that I am using and the old XP is just for a few things Xp does that Win 10 doesn't. Friend suggested heat, but 30 seconds? It is kinda dusty, but 30 seconds?

 

Definitely sounds like a heat related issue to me.... I would leave cmos related auto shut-off features enabled while checking for fans properly working first (CPU fan especially). I would also check the system clock in the cmos setup to see if the time/date are correct to start with, and if they repeat after cold boot. (failed cmos battery can cause all sorts of little issues).

Also note, dust is a very good conductor!!! You might want to unplug that unit and give it a good cleaning.