My wife's HP is not that model but similar specs. However your machine appears to be in sad shape.
The overclocking is the lesson learned and the new board is suspect now. I'd return it for another.
Bob
Specs
hp envy 15-1270ca
intel i7-720qm 1,6 Ghz turbo boost up to 2,8 Ghz
wd blue 500gb hard drive (also tried with toshiba hard drive)
ATI Radeon 5830 discrete graphics card
4 x 2Gb of DDR3 elpida ram
I recently bought a new motherboard after breaking the other one by overclocking the gpu.
Even with a new motherboard the computer keeps turning off after a few seconds

Chowhound
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