Every time I try to save files to my portable hard drive on work computers (Intel Xeon Win XP SP2 machines with deep freeze on the c: drive) the computer says it's saving to the hard Drive and gives an appropriate amount of moving time but the HD lights don't flash and I hear no activity. When I look at the drive the file is there and can be read. However when I turn the HD off and then back on it dissappears. Occasionally it will successfully write to the HD and stay there. Moving large amounts of data i.e. several movie files seems to have a bigger chance than say a single picture.