HD Memory PSU
I have had a HDD drive fail, it was 80MB... but, it didnt really have anything important on it. This computer was from the 80's, but the HDD was from the early 90's. IBM!
Also, I have had memory fail, (Hyundai, why have you failed me,) probably due to improper handling...
I have had a PSU fail as well, and still have failed to fix it. Gateway!
My custom made computer (brothers friend built it a long time ago) is my server, its PSU does not function properly. You have to let it sit and start up, it just sits there and moves back and forth, but, it gets going. My molex cable fan pulls enough air through the PSU and the rest of the case, its not like servers sit and overheat or anything.... (or do they...)