It's a Dell XPS 700. It was originally a Core 2 Duo 2.4ghz with a HD 5850. I changed the video card for a GTX 1050Ti and the CPU for a Core2Quad Extreme 2.93ghz. Now it seems to like randomly shutting off or rebooting itself. I'm thinking the CPU is more likely the issue since the GPU draws less power than the one that was originally in it. The Dell PSU that is in it is rated for 1000W, so it should be supplying enough power, unless it's completely worn out. Any ideas?