I've been running 2 identical capacity hdd's on my XP sp3 computer for a couple of years without any drama's. Recently had a problem with a usb stick that came up as write protected. Since then the second drive doesn't show up in "my computer". My primary drive is F, secondary was C. Disk management shows F as Disc 0 149.04 gb ntfs and an unnamed volume as disc 1 no file system indicated and only 28.63 gb.