[Help] PC hang without errors

[HumongousLips]

Hi. My PC recently keep hanging suddenly, then restart after ~1-3mins of hanging. Even at Loading Windows screen, it hangs at times. No BSoD.

Suspected it is GPU failure, so took it out, and used on-board graphics card, and everything run smoothly. Could this be a GPU failure or Power Insufficiency issue?

 

[jtjt00]

High chance is GPU fault. Sapphire GPU has 2 year warranty only.

 

[HumongousLips]

means ggwp and time to buy a new GPU or buy a brand new PC?
given my specs, still worth upgrading to the following? :
1. sapphire r9 290 tri-x and get a new psu for more juice.
2. RMA my 7850 since still got 2 months warranty.
3. get a brand new pc
4. forget about all 3 options and just do my gundam modelling.