Power supply perhaps ?

My wife has a HP 511n that is shutting down intermitently with no blue screen or any such info. Once it is down the cord must be removed from the power and plugged back in to get the computer running again. I noticed that the fan was not running on the power supply when I started the unit up but on further examination (and time) see that it is running now that the computer has been on for a bit. Might this fan be bad and is there a way to tell or am I on the wrong track?
Thanks for any suggestions or instructions (web pages etc,) that might get me to the other end of this problem.
KennJ

It sounds like your power supply is tripping out from what you describe. After that happens, the unplugging from the mains is what you need to do to reset them. It could be a faulty power supply, but it could also be damaged cable insulation causing a short circuit, or a faulty component causing an overload. Carefully inspect all the cables. If they're OK, unplug everything except the CPU, RAM and graphics card (with the power disconnected of course). Then reconnect each disconnected item until you find which one is causing the shutdown. If none do then it's the PSU.

Looks like I got it back to working. I took apart the power supply and cleaned it off . Checked all the wires and did not find any trouble but once I put it back together and in the computer it has been working fine. Must have been a short that I took care of when I cleaned it up.
Thanks for the suggestion.
Kenn

You're very welcome. I'm glad that you got it sorted out :)