Random crash happening.

Thor68

Honorable
Oct 8, 2013
18
0
10,510
Ok so my buddy bought a lenovo K450 series desktop a few weeks ago and we upgraded the power supply and graphics card not long after he purchased it. There have been zero problems up until today. I guess as of last night he has been suffering random crashes for no reason. He told me that the crash starts with his pc lagging insanely bad then just freezing up and crashing all together. To me this sounds like it might possibly be the OS or CPU since it just happens out of the blue without any links pointing to a cause. I was wondering if anyone might know what it could be or how to fix it?