Experiencing a new/strange problem. When I open a previously saved Excel file from mydocuments folder I get the following warning and can't get to the file so I can edit it.

"File in Use: File.xls is locked for editing.
by John Ellis
Open 'Read-only' or click 'Notify' to open read only and receive notification when the document is no longer in use."

I have tried everything I know how to do to get this locked file unlocked.

Any advice appreciated how to fix this.