Dig your manual up, the CMOS reset may just be a case of unplugging mains lead, moving a jumper (usually found in close proximity to the CMOS Battery) from pins 1 & 2 to 2 & 3 for a few seconds, then putting it back on pins 1 & 2 and re - applying power.
Some boards however require battery removal, and/or leaving the jumper on for a 30 minute period (on really awkward ones).
My system is still a little suspect, this 2nd hand board will light up when power is applied.
But won't jump into life for up to five minutes after the button has been pressed, a bit like me in the mornings except quicker!