Not practical now maybe, but Steve has a point. A newly bought Dell PC should rev up fine.
If you have your files backed up, and it's a new system not working right, bring that sucker back into the store. Get a refund.
Buy another. I'm lucky enough to have a computer store nearby. I choose the case among many on the floor, then liquid cooling ,CPU, motherboard, graphics card, memory...and just pay the store $50 on top to put it together in about an hour. Fry's.