I had exactly the same symptoms.
It turned out to be a sticking escape key.
Check it out. Hold down the escape key and try and drag and drop.
Regards
Ailuro
Someone linked in 2010 here:
http://it.thelibrarie.com/weblog/2010/06/drag-and-drop-stops-working/
That was then linked in 2011 here 2011 here
http://answers.microsoft.com/en-us/windows/forum/windows_7-performance/drag-and-drop-not-working-in-windows-7/f6dcfa11-8c51-e011-8dfc-68b599b31bf5
I brought it full circle in 2012!
This plagued me 6 times a year for years.
Thanks.
/sry old thread




