Can A Bad CMOS Battery Shut Down A System?

no it wont..most times when you have a shut off is due to an over heat or a part failure. i would see if the mb is posting by pulling the video card out first and see if there any cmos beep codes.(if you have a speaker on the mb). or if there some fault led. if it not the video card if it works in another pc or you put in a new video card and mb still does not post. it may be one of the main chipset on the mb failed or a cap. check on the mb chipset for any burn marks.

Thanks for the reply. I didn't think so, but I was hopeful as I'm up against a wall with diagnostics. Have done a breadboard test, and have ruled out my PSU.

Left to determine whether it's my ASUS P6X58D-E or Intel i7 P960. The MB's onboard system-on switch is illuminated red, but I have yet to hear from anyone or find indication that is abnormal or is indicating a MB problem. Do you know.

Sad thing is, my retail supplier has advised me that my MB, or an equivalent, is no longer available new as the socket as been discontinued. If thats the case, I'm looking at a new MB and related processor. My system is sadly just over a year old and not even paid off yet.

how did you test your power supply. if it was the paperclip test that only will show that it will power up. you can still have a bad leg or a weak leg on your power supply. the asus mb should still be under warranty the board should have a three year warranty. if your mb has a speaker that does the cmos beep codes..if you remove the ram and video card it should beep at you if it posting and has power. ask your local computer shop or tech person if they have a post it card. if the mb has power and is trying to post one of the post it cards will show you that it posting or not and the error code of where it locking up. cpu from intel dont roll over and die..most time there fried from no fans or bad over clock. most time is the cache in the cpu that goes bad and you get blue screens. our issue sound more like a cap or power on the mb went bad.