Trash

I recently trashed all my very old backups..one file was in the process, many moons ago, of backing up and now it won't delete because it 'is in use'..problem is it is stopping all the other back up files deleting and also now making my computer so slow its almost impossible to use..any ideas on how to remove it from the trash permanantly? Please help.

I presume you've rebooted since you've had this problem and it still persists?