Chances are it's broken because you keep getting them second hand. That isn't meant in a harsh way or anything, however, it's not like you hear hundreds complaining about their Asus Mobo's dying...
You tried resetting the CMOS? Might be that your overclock wasn't liked...
kd
yupp done allot to try and stablise the system, i have a grudge against asus, not everything i buy is second hand but from what ive seen that on the lower end boards (£100-ish range) that there are a lot of design faults and they always end up breaking. weather there second hand or not shouldn't really make much of a difference, other than the asus boards there was a 15 year old dell working perfectly, a intel 775 board and a asrock 775 that have died on me, it just shows something about there build quality and lifetime, if most other things ive had in the same joblots.ect have worked.
actually i praise some of asus higher end boards, i had a am2 board some mn32 sli or sumink along those lines that had been hugely mistreated the wifi card in it had a rusty heat spreader/cover on it to give you an idea, and that seemed okay, for about maybe 3 hours before exploding on me due to age, witch was only about 3 years.
honestly it wouldn't really bother me zzzac, as the chip alone is worth more than you bought the pc for
yeah, im not really that bothered, bit annoying but im advertising the chip on the bay for £80 witch is the going price on ebay, so, and i got a case, a cooler and a board that will probably go to a mate in an atpemted repair, not sure anything will work although, im actually quite tempted to switch cases from my stacker to the thermltake but im not sure i can be bothered
but why can't gigabyte make a z68-oc?! 
