Can Excel run vba without updating the screen or causing it to flicker?

You can put this in the beginning of your code:

Application.ScreenUpdating = False 'hides what happens
Application.Calculation = xlCalculationManual 'excel doesn't save

At the end of the code this is inserted:

Application.Calculation = xlCalculationAutomatic 'Turns on the calculation again
Application.ScreenUpdating = True shows what's happening again
DoEvents
Application.Calculate
DoEvents