Am I able to change a Serial ATA RAID 1 w/dual 160GB Drives

I have a Dell PC that has a NCQ Serial ATA RAID 1 with dual 160 GB Drives. Look redundant to me.

I would like to have only one drive for the OS and use the other for backup and other uses.

Is there a way a person with little skill with PC can change this around? I don't want to have to reformat, just use one and clean one for the backups and etc.

I have an EZGig 11 backup program that will allow me to Clone a Disk as well as backup particulars. I want the second disk to Clone my system. I'll have it made if this can be.

I'm an old Geezer with little or no skill with such as thing.