when I open a excel file, my screen starts flickering. I did office repair but didn't help. I tried to open the same file on other computer, no issue... what could be the problem?
A Workbook_Open sub won't appear in the Macro Selector dialog, so you still aren't able to dismiss that possibility.
To eliminate macros as a potential cause of the problem:
1. Save the file as .xlsx file format. This will remove any and all macros from the saved copy.
2. Quit Excel
3. Relaunch Excel and open the .xlsx file. If it doesn't flicker, then macros in the original file are the cause.
Another thing you can try is to type Alt+F11 or click the Visual Basic button. You'll then be in the development view. Find 'ThisWorkbook' on the left and double-click it. In the code find 'Private Sub Workbook_Open()' and click in the left-hand margin of that sub. Click somewhere in the sub and then press F5 which will start the process that the workbook goes through when it opens. From there repeatedly click F8 to see, line-by-line, where the code is going. I suspect it's in a loop.
Microsoft Excel topics include formulas, formatting, VBA macros and user-defined functions, and everything else related to the spreadsheet user interface, including error messages.