Seems like your recycle bin is corrupted. The original (Microsoft) remedy for this is:
1. Open a Command Prompt window. (Run as Administrator)
2. Type the following command and press ENTER: rd /s /q C:\$Recycle.bin
This will empty the recycle bin folder from the C:\ partition. If you have more than one partition or HD, You may have to do this for each .
If that does not do the trick, you can try Ccleaner, which incudes that function, or, longwinded, try the well known SFC /scannow to refresh all your Windows 7 files. This is time consuming, but very thorough. If you have been attacked in any way, the last will probably take care of it.