Hello, so, my pc was working fine(like 5 years), i have two hds installed, one with ubuntu and other with window 7. One day, i turn on the pc, and a black screen and underscore apear,so i open the case, and turn on the pc, and was ok, when i put the case back, again the underscore, the case has a fan, so i disconected and everything was fine. Months later, again, so i unplugged the dvd lector and was ok for a month, know im having the same problem, sometimes just turn ok and work for hours with nothing, and sometimes the underscore apear, or a read error apear, or it get stuck in the windows logo(i just tried until it work). I read, that maybe the PSU its failling and not providing the correct power, i want others opinions, because buying a new PSU here is expensive. Thx!