please run kb947821 and post the CBS and SURT logs, ill have a look.
from C >>Windows >> logs >> CBS >> in the folder copy/paste, top cbs and bottom SURT
and run this as well please, http://go.microsoft.com/fwlink/?LinkID=52012
I'm not sure which one you wanted, so I'll post them both.
Besides keyboard (USB2.0) and mouse (USB2.0) I also have a permanent external drive (USB3.0) plugged in for Windows 7 Libraries.
Should I retry sfc /scannow without the external HDD?