I need to set up a domain can I do this with linux?

I got this dell power edge 800 server off eBay and it has Windows Server 2003 on it and it is password protected. It has a adaptec raid controller with 2 SATA 80G harddrive configured in a raid 1. Can I reformat the harddrives without accessing windows and add 2 more SATA 80G harddrive and do a raid 5? I also want to set up a domain with the server using linux. Is this possible? If so, how?