^^ @aeadds, You are absolutely right.
Nobody seems to know exactly what causes this problem.
OK, what are the fixes tried?
One user says that he reinstalled Windows with the USB device plugged in and that worked. Looks like a drastic solution. He is emphatic that it is the only solution. All else failed. I chuckle.
Another user has the same problem when he plugs in his new USB Keyboard. He reinstalls Windows with the device plugged in. Problem resolved. My chuckle stops. May be there is some truth in it.
Microsoft suggests a clean boot to check whether any third party program is the cause. Also suggests that you disable any or all security software be it anti spyware, anti-malware, firewalls by whatever name they are called and so on.And then the usual SFC Scan now to repair any corrupted system files.
Another user says that disabling System Restore, resolved the problem.Someone else rebuts that it did not work for him.
Another User - I restored my system to a date prior to the appearance of this problem and it worked.
So the problem lingers.
So finally when one does not know the cause, one has to try and keep on trying all suggestions and so here is my bit - which no one seems to have suggested so far. Here it is
http://www.sevenforums.com/hardware...al-drive-not-recognised-boot.html#post1785801
If it resolves your problem, you hit the jackpot and me the rep-pot.
BTW, how does stewartd change to aeadds? !!!!!!!