the C: drive in my windows XP computer (the one with the OS actually on it) is only 75-ish gigabytes, and its running out of room. i want to copy it all onto my empty 250GB USB HDD, and i also have a second (full) drive called D: . i'm pretty sure i cant just copy all fo the files onto the new drive, plug it in, and boot windows off of it... so how do i do it? what program (preferably free, but not necessarily) can i use to do this? what sort of BIOS fiddling will i have to do? please help.