I just doubled the memory in my Terminator, too, denmo, and when the machine boots, it recognizes the new memory automatically (to check, right click on My Computer and choose Properties. The page that comes up will tell you how much RAM you have).
As to the harddrive, presumably if it is not formatted and the OS not loaded, you will be prompted to do so at boot. I seem to remember that from when one of my RAID drives went bad and I installed one large new harddrive in lieu of the previous two.
Hope this helps.
Newly