You've found a stray file you no longer need, and tried to delete it, only to see an error message like "Cannot delete file: Access is denied," or "The file is in use by another program or user." Annoying, isn't it? Especially if you can't figure out exactly which application might be holding on to the file.

Don't give up just yet, though -- the answer may be closer than you think. Especially if you've a copy of the (newly freeware) File Governor to hand.

Launch the program, click File > Search for Locked Files, and select the folder containing your troublesome file. In a second or two you'll see a list of locked files in that location, and any subfolders, along with the process accessing them. And if you recognize the process that's opened your document, and it's not anything system-critical, then simply closing it will allow you to access the file again.

If you've no idea what the process is, or it can't be closed, then File Governor can unlock the file anyway: just right-click it and select Handle Options > Unlock, and again the file will be yours to delete, rename or otherwise manipulate.

Alternatively, File Governor can tell Windows to delete the file when you next reboot (just right-click the file in question, and select File Options > Delete > Reboot Delete).

This kind of tool comes in very useful if you're trying to manually clean a PC of malware. viruses, trojans and similar pests will often go to a great deal of trouble to protect their component files, but File Governor should allow you to bypass all that and wipe every trace of them from your system.

You do need to be careful in other situations, though, as there's no way to tell how an application might behave if you unlock (and maybe delete) a file it was accessing. It could carry on as though nothing had happened, but it may display an error message, or even crash your entire PC. There are no guarantees, so use File Governor only as a last resort, and after you've saved any open documents.