My Verbatim 1TB USB External Hard Drive was hanging my PC at boot message "Auto Detecting USB Mass Storage Devices... Device #01. An old thread found on this forum had a similar problem with a WD 1TB My Book. The solution found then was changing the BIOS setting to DISABLE Legacy USB support. When I checked my settings I found my Legacy USB support was set to AUTO. Following the prior threads success I changed the setting to DISABLE and the problem was solved. Apparently when faced with the choice of Enable Disable or Auto, the Auto setting doesn't always choose the appropriate action. Thanks guys and gals for a great forum site.