I am using this bit of code to open a workbook where the path and
workbook name is in cell Y8
Workbooks.Open Range("Y8").Value
ActiveWorkbook.RunAutoMacros xlAutoOpen

However I want to do 2 things
I need that if the workbook is already open the selected workbook is
just activated, I must not have the option to open the workbook again
and overwrite the changes made to the open workbook.
If the file is not found, I get an error message and the macro must
then end. The debug option must not appear.

Help will be appreciated