Member Avatar for stevenkgray

This unit shuts itself down after a minute or so. If I try to start it back immediately it only runs a few seconds.

I noticed the Heatsink holder (plastic) was broken and not allowing any cooling to the CPU and replaced it.

The unit and fans are all clean.

I changed out the Memory sticks with no change.

I replaced the ac cord with no change.

Any suggestions?

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Dani AI

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As suggested, a poor thermal interface or bad heatsink contact is a very common cause of a system shutting down early in POST. Confirm whether the machine is dying from overheating before swapping major parts: look at BIOS hardware-monitor temperatures (if you can reach BIOS), watch the CPU fan on power-up with the case open, and note any POST/beep behavior that changes when you disturb airflow or fan connectors.

If thermal contact is suspect, follow a careful reseat procedure: power down and unplug, ground yourself, remove the heatsink, clean mating surfaces with 90%+ isopropyl alcohol and a lint‑free cloth, apply a small pea‑sized amount of thermal compound to the CPU center, and reseat the heatsink straight down so it makes even contact. Fasten the retention evenly and reconnect the CPU fan to the proper header so the board can control and monitor fan speed. Avoid excess paste or substitutes (no glues or household greases).

If the problem persists after proper reassembly, isolate other common causes: test with a known‑good PSU or measure the 12V/5V/3.3V rails with a multimeter, inspect the motherboard for bulging/leaking capacitors, and try a minimal boot (one RAM stick, no drives, onboard video only). A short, immediate shutdown under any load points toward PSU or motherboard/VRM failure; a shutdown that only appears under load points back to cooling or a thermal sensor/BIOS setting.

Safety note: always unplug and let capacitors discharge before probing. If unsure about the steps above, a shop can quickly verify voltages and heatsink mounting and save time replacing parts unnecessarily.

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Member Avatar for compdoc

did you put thermal paste between the heatsink and the CPU.

Member Avatar for stevenkgray

did you put thermal paste between the heatsink and the CPU.

Nope; I didnt have any. I thought about it but hoped it wouldnt make that much difference. I assumed that the heatsink being attached right again might work.

Guess not huh; maybe.

Member Avatar for compdoc

na you should apply some themal paste it makes a difference. unless there is something else wrong with the computer, but the first step would be the termal paste.

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