My Seagate backup drive was replaced under warranty, but the new one, if attached, prevents windows from booting with a hang just before the blue "Windows is starting" screen. The old drive did not do this and the replacement is identical as far as I can tell. One of my USB pen drives also causes this problem both on my PC and another - but is only rarely present for boot.
How can I fix this? I wonder if an update has caused this - that backup drive was off the system for many weeks while getting the replacement so I have no close time frame for when the system became fussy!
THe BIOS is set to boot only from the usual HDD.