Originally Posted by lodore 
any idea why i cant post once i change sata to AHCI mode?
I've seen this many times. Often SATA ports have different controllers - some will be one colour and controlled by the southbridge directly, others a different colour and controlled by a jmicron chip. Try switching your hard drive to a different coloured port first of all. If that doesn't work, try disabling the jmicron chip (if there's a bios option for that) - and then try switching ports again incase you're now using the jmicron ports.
Failing that, try updating the BIOS, but AHCI has always caused me more trouble than it's worth.