My USB HD is full, now Vista doesn't "see" drive-Problem Solved! Help. I have been using Paragon Drive Backup 10.0 free edition for several weeks to back up to my Samsung 250 GB SP2504C USB Hard Drive. I think my HD is full, worse, now Vista doesn't "see" my drive. The weird thing is that when I attach the USB drive, Vista chimes, and when I want to remove it, Vista recognizes the drive but doesn't assign it a letter. It used to be G. I have my C drive for my programs, a D drive from an old computer, and my E drive for data, and F for the DVD drive. Why doesn't it recognize the external drive? Thanks everybody.