Here are things i would try and you have done so on several:
1. vidcard drivers- make sure compatible with your pc brand too if its a prebuilt aka dell/hp etc. also correct driver for your OS. my laptop will not accept the new driver yet bc its an HP. make sure to do a clean install of drivers.
2. vidcard- maybe bad card or overclock. try with another card or place your card in another pc to see if the prbm transfers to that pc.
3. PSU- your psu should be fine to run your stuff but if its bad or weak then replace it. u can buy psu testers. only way to test it is to place loads(voltage demands like video card/motherboard/hdd etc) on the psu. the psu tester will apply loads to it and see if it fails. also you might find a pc repair shop that will test the psu for you.
4. possible but unlikely is a bad motherboard. try placing card into another slot if you have it. also make sure your card is in the correct slot but really shouldnt matter.
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Rift-Gnarlwood (G):Joncrichton, Aerysunn, Rigel, Kahdargo
i7-920 3.8GHz, air-cooled Everyday im husslin'