Not sure if this is hardware related but I'll try posting here ...

On boot up, my Samsung LCD monitor light just blinks and the monitor itself will not start. On second boot up the monitor starts just fine but the computer's time and date has changed itself to 11pm December, 31 2006. This happens randomly. Sometimes I can go four or five days WITHOUT it happening. It's not the battery. I had it checked.

Any clues or help would be appreciated.

ThanksHave you ruled out viruses?What battery did you have checked ? ?
Sounds like a failing CMOS battery to me...I agree with patio.  You replaced the battery too, right?i'm not a pro like them but i experienced that kind of problem with the unit of my friend and i changed his cmos battery then its ok..

if your absolutely positive it's not the battery, it could be the POWER supply, too. Normall the PSU keeps the CMOS RAM refreshed instead of the Battery while it's on; if it doesn't provide enough power then the CMOS RAM can be lost.I purchased a new battery and installed it. No difference. I even had the old one checked and it was still good. My computer is only two years old.

I did have some problems with a MEMORY test. I tested all 4 sticks separately and found the third slot or bank was producing a memory error. Since I've removed the stick from that slot, memory checks out okay.

I have scanned for viruses with Windows Defender and Windows Care. Seems to be no problems there.

I checked the power supply via the BIOS settings, It shows voltage being just under 12 watts. Not sure what that means as I have a 600 watt power supply.

I'm starting think possible motherboard failure.

First person that solves this mystery gets a free beer! :-)

System specs: ASUS P5N-E SLI motherboard, Vista 64, Quad Core [email protected], ASETEK LIQUID cooled, 4 GB DDR2 Crucial Ballistic RAM, 1 DDR2 GB Buffalo RAM, Nvidia 8800 GTX I haven't seen a motherboard that measures the PSU OUTPUT in watts...

They do show voltages, however, and one of them is the 12 volt rail.Were all MBoard standoffs used when this was assembled ? ?
Is the PSU new or used ? ?
Have you visited the ASUS forums for similar issues ?