Open unopened file

At a certain stage, my program prompts user to open file "FileToOpen" where "FileToOpen" is a string variable assigned to the name of a certain file. In order to get to this point, I use the command: FileToOpen = Application.GetOpenFilename(<various filters>)

If FileToOpen is already open, I get a system alert asking user whether thy want to overwrite FileToOpen. Rather than suppress the alert, I want my program to do something like this: (

(Sorta using English here instead of VBA so please disregard the lack of formality):

'IF FileToOpen is not open then open FileToOpen; Else don't open anything.'

I suspect I am asking the impossible, but any ideas would be appreciated

Thank you TMShucks. Your post was helpful, but I'm keeping the thread open as I'm still hoping against hope to get exactly what I want.