PC not rebooting

[fangio99]

Current Spec

Antec Sonata Elite Case
Antec Truepower 750W PSU
Asus P5Q Pro motherboard
Intel Q8200 Processor
Kingston HyperX KHX8500D2K2/4G 2x2GB Ram
2x WDC Caviar RE2 GP 1TB hard disks in RAID1 Mirror using Intel Matrix Storage Manager
LiteOn iHAS322 DVD/RW SATA drive
Sapphire Radeon HD 4850 1024MB PCI-E
APC Back Ups ES 700VA
5.25" Front panel Card reader with Esata and USB ports
Samsung 23" Screen

So far the hard disks, the PSU and the UPS have been replaced. The CMOS has been cleared countless times.

The PC works fine except for not rebooting. It reboots from the OS with no problems but if I enter the BIOS even to check the settings or boot from a CD, it wll not reboot at all. No lights, no activity, no display but the PC is on. It doesn't even do the POST. The only way to clear it is to remove the power connection completely for around 30 seconds.

Please anybody got any ideas before it goes out the window. This is a brand new system that has never worked properly.

Fangio.

Post Edit

[timon]

Normally such problem occur due to psu but as you have Antec Truepower 750W PSU , it is best now another thing is bios update but as your configuration is new try to claim replacement for Asus P5Q Pro motherboard as there may be problem exist.

[SecRecy]

Just see try ti check ram if dust is no the memory bank. if there is clean all of it bank(slot) and RAM .And update your BIOS .

[BertieStan]

First of all XP Pro is a great OS. Secondly, internet explorer (unless you have acess to the 64 bit IE) is vulnerable to malicious attacks. I would first off use the FireFox 3 for the internet. You may have a virus that attack some system files, or you may have to find some new device drivers for some of your hardware. The most common problem with PC reboots is that your AC power from you power outlet is below 110 volts. Your AC volts from the wall outlet have to be 110 to 120 volts in order for the computer to function correctly. Anything below 85 AC volts causes hardware failure.