why my computer keep turning off?

[ET]

when i turn on my computer it shuts off this lasts for 10 20 sec.I opened it up and and cleaned with dust air power supply also cleaned.I think it maybe defective power supply does anybody think it may be something else that I over looked.
NOTE IT DOES NOT EVEN BOOT UP.

[Geek Squad]

Hey et, from my experience there's only a few things that can cause a computer to shut off on its own.

1. A bad power supply (and/or charger with laptops).
2. The CPU thermal compound has dried up and needs to be cleaned (have only an expert perform this cleaning).
3. The OS isn't finishing it boot process and is sending a restart command to prevent an error.
4. A short circuit.

...I'm sure there could be more but none more that come to mind but when I see this happening its usually something thats not a simple fix.

Agent Jeremy D
Badge 32326
Cadet
Geek Squad Social Media Team
2/8/2014