|I've not run into this before. Seems to be widely reported on all manner of HP computers but with few definite fixes. I did find this, which may or may not help:|
"I found that one of the ribbons inside can become loose and cause this. This ribbon is located under the plate that houses the power button. It is the second ribbon on the right. Try cracking open the pc (you only need to remove 5 screws and loosen the 3 kb screws to get inside) and making sure that the ribbon cover is not off or loose. This will only apply if your power button light stays on even when you turn it off and if your HP Tools is disabled"
You might not fancy doing the above.
A BIOS update is often suggested (without any further sign of this fixing anything) but that is risky. It would seem odd to suddenly have to do this when everything worked before. BIOS updates are very rarely necessary.
Sorry, other than suggesting Google for "BIOS Application Error (501)" it's hard to come up with anything useful. Keep watching for other ideas (or finds).
Always pop back and let us know the outcome - thanks
message edited by Derek