I am sorry to hear you are having problems but let me help you.
This is a strange behavior that seems to be a board problem. I recommend checking all bios and chipset software are up to date.
In regards the Raid question, if you set a RAID and at any point you need to reset the bios, in fact it will change the chipset mode from RAID to AHCI; however, the HDDs are still under a volume and the structure of the Array will be in the drives so all you need to do is to change the Chipset mode back to RAID and by doing that you can boot again the volume. Basically resetting the bios to default will not make you lose the RAID.