Application.ScreenUpdating = False is not working

Hi all,

I googled my problem, tried different solutions but still have this problem :

I download a CSV file from Yahoo, called quotes.csv, and save it on desktop.
Then I open another workbook, Wkb1.xlsm, which has a macro that opens, updates and saves the quotes.csv workbook.
My macro starts with Application.ScreenUpdating = False , but selecting each workbook back and forth, I get an annoying screen flickering.

Appreciate your help.

I solved the problem by NOT activating each workbook while reading from one and writing unto other workbook.
Hope this could help someone else with the same problem.