Quirky PC issue

[Polar Bear]

We have a Medion PC running a dual core processor, 4gb ram and a 1gb graphics card.   It runs Win XP very happily and serves us well.

It has a little bizarre quirk which happens about once a month - it manages to get confused and not be able to start up.   This seems to happen if it goes into hibernate mode whilst having a device such as a mobile or an mp3 player connected to any of the front panel usb ports.   The solution is to switch the power off at the mains, wait a few seconds and restore power.   It then starts first time on the touch of the start button.

Any clues mainly out of curiosity please? 

[barakta]

That smells like USB bus confusion after a hibernate state.  Hibernate is voodoo as indeed is starting up with usb devices connected.  I think most PCs I use (home and work) have a startup glitch about that often and if it recovers with a restart or power down and up then I consider that about as reliable as the species get.