Try this:
Drag & Drop issue might occurs if you are running applications with elevated privileges, since Windows, for some security reasons, prevents lover privilege applications to interact with the ones with higher privileges
You can fix this by disabling the UAC completely In registry editor find HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows > CurrentVersion > Policies > System, open the Key EnableLUA and change the Value data from 1 to 0
Just be careful with this if you are using Metro applications, as this tweak might break these
Quoted from the solution posted on http://superuser.com/questions/654124/unable-to-drag-and-drop-select-multiple-with-mouse
I had the same problem, the ctrl-escape worked, but only for a few minutes. Changing the EnableLUA register seems to have fixed it permanatly.