SRS:
Another way to handle Hard Drives is to install a hard disk 'inner rack' into one of the 5.25" bays in your PC tower. Your hard drive fits within a small enclosure which slides into the rack. The enclosure gets its power from the PC box itself and contains a cooling fan. This allows you several choices. You can have your main hard drive in this, which means your computer won't boot without it, and you can have several different systems, each within its own hard drive. You can also have a permanently mounted hard drive with system on it, and a second 'plug-in' hard drive which has all your data. The racks are inexpensive and you must have your system powered down in order to mount or dismount the hard drive. I utilize this kind of rack as well as the USB or firewire external drives.