Hmm, I don't know why you would get a partial boot if going to the wrong drive, but have you checked your boot priority in the BIOS? Is it possible that you didn't install Windows 7 where you intended to? Personally, I prefer to install an OS on a drive with no other OS on it, and with all other harddrives disconnected during the installation, then use either the F8 BBS Popup Menu or the BIOS Boot Priority to choose the OS to boot from.
If it really is installed on G:, it sounds as though that something went wrong in your boot manager, but if that is the case, you will need to wait for someone else to chime in, because I'm not sharp enough on that aspect yet.
EDIT: Thinking further about it, I'm sure that you didn't disconnect the other drives, otherwise Windows 7 would be on C:, just as XP is. Windows seven wouldn't have a different drive letter, unless booted into XP.
EDIT 2: It just sank in that you only essentially have one harddrive...the array. If that is the case, where does the external drive fall into place?