I had the same problem and it took me a couple of days to figure out I had to reformat and repartition the drive. What I had done was use a WD utility to “zero” out the data. It zeroed out everything. I have XP and it’s done from the device mgr. I forget exactly what steps to take and it may be slightly different for your operating system. But you should be able to get help from windows by searching for format, device manager, partition. If you can’t find it from windows look on the web. Even though explorer can’t see the drive, the device manager will be able to see it as long as it connected. BTW, by doing this you’re going to lose all data. As far as I know it’s your only option. It shouldn’t be too big a loss if your main drive hasn’t gone during the interim. Also do a quick format unless you want windows to check the drive for errors, sector by sector. It takes a long time that way. Best of luck!