I'm trying to setup RAID 1, and while trying to save, the BIOS asks me to clear MBR. I looked it up, and it means (I think) master boot record? Should I clear the master boot record or leave it alone? This computer is completely new, just built, so I won't lose any kind of data if I mess up. Thanks.

you can not set up raid1 on a all ready built system - you need to wipe the drives.

is that what you doing? trying to convert your system to raid1?

patition the drive and make the raid1 with part of the drive that does not have the os, you have back up on the data you put on the raid1

you can not make a raid1 with an existing os the raid is below the os

^ Agreed.