W2K and W2K3 Sharing Violation

Good Day,

I tried to delete a newly created excel file but failed, and it says:

"Cannot delete <filename>: There has been a sharing violation.
The source or destination file may be in use."

This is a file server, I could not reboot it all the time to resolve this issue.
I have tried to use unlocker, but that does not seem to work.

Does anyone face this problem and know how to resolve this?

thanks,
stel