Why wont my trash can empty?

Hi. I am trying to empty my trash can and delete an AVI file, however I get the message: "The operation cannot be completed because the item 1.avi is in use".

I have tried restarting my laptop several times, I have moved the AVI to the desktop, put it into a folder, renamed it, tried to delete it, and still I get the same error message.

The AVI file is definitely not in use (I don't even know what it is, it wont open to play).

I have Leopard 10.5.8 running

Please help,

Thanks.