Cannot drag and drop files

This problem emerged recently. When I attempt to drag and drop any

inconspicuous file from one folder to another absolutely nothing happens.

When I attempt to cut and paste instead, I get vista telling me the file is

in use - "The action can't be completed because the file is open in another

program." I can return several hours later and even sometimes after a reboot

and I still can't physically move the file. This is for any file type. Very

annoying.