Why does my screen update with images even though i have screenupdating turned off

Hi, i have a macro and at the begining of it i turn the screen updating OFF.

However, at various points in the macro my screen still refreshes with images......is there something that can turn the screen updating "back on" even though i have told it to turn off?

What about displaying of alerts..........this does not turn screen updating on does it?

any ideas?