I'm trying to change the boot drive on DP35DP motherboard but I can't seem to get it to work reliably. The system has booted fine from either drive and I've verified that the both drives boot on another machine. I shutdown the system and unplug drive end of the power/sata cables from the boot drive (leaving the motherboard socket unchanged) and plug them into the new drive. Most of the time the system won't even try to boot, as though it can't find a bootable drive. After the BIOS splash page it will just sit with a cursor in the upper left corner. After struggling and trying everything i can think of the drive boots, but then swapping back I get the same problem.
I have 6 sata drives installed and 1 IDE. It seems that the motherboard isn't sure which drive to boot from and is often chosing the wrong one and hanging. Ideas?