Failure to start - power supply failure ?

[Franz47]

Yesterday and today: Desktop, pressing start button brings about BIOS-screen, HDD LED blinks a bit, DVD-drive activity audible for a short while, then complete silence, system not active in any way any more. I could reproduce this behavious several times. I probably do not have a working system loudspeaker any more. At least I could near any BIOS beeps. Turning off all power lines to the computer for about an hour and then powering up again made it start again as usually.

Is this a symtpom of failure of the power supply? In the meantime a backup is running and I have brought my laptop up to date to jump in in case the desktop fails and becomes unresuscitable. I am ready to replace the power supply but only if there is enough reason that it is the culprit.

 

[Franz47]

After running with the backup through the night I turned off the computer this morning. Same restart problems again as yesterday. BIOS windows appears, therafter silence or no reaction to start button at all. Again after switching off power to the machine completely for a while it started as usually.