Sys shutdown/bios issues

[wiscountryboy]

hey guys, i have a asus a8n5x mobo when i try to shut the machine down, the system locks up when windows xp says "windows is shutting down" so naturally i press the reset button and the system restarts, the only thing is that now bios will not post and the only way i can get the machine back on is to flip the switch on my PSU and start then, i have already checked the power supply with a known good working one....

i have the above mentioned motherboard, a 3800+ x2 a gig of ram, 80gb sata hd, 350 watt psu, a 7300le graphics card and a single optical drive

 

[frankibo]

Have you tried to set your BIOS settings to set to default. It may be a setting in the Power Management.

 

[wiscountryboy]

yes i have tried that....