I use shell to open text file with Notepad. It works, but if I have already Notepad open on my computer it doesn’t’ show up. Probably I need to check if Notepad is open, then to close the Notepad with VBA code and then to run shell. All files are on the SharePoint.

I can only suggest you look at API calls in VBA...
Not dabbled in them nearly enough to help just yet but I'll be interested in knowing the answer also.

http://www.mvps.org/access/api/index.html