Stopped the flicker then added a protect/unprotect to the macro and flicker started up again??

[RobbieNZ]

Hi there, I have the code below that hides rows if the test cell is 0 or blank.

The screen on sheet 1, which drives the results for this "Q U O T E" Sheet, was flickering badly when every drop down box or tick box was selected. I Fixed that with "Application.ScreenUpdating = False"
However, I now want to protect the sheets and tried to add the below:

Sheet8.Unprotect Password:="Secret"
my code
Sheet8.Protect Password:="Secret"

This created really bad flicker again and then I started getting a 1004 runtime error on
Rows("1:" & Worksheets("Q U O T E").UsedRange.Rows.Count).EntireRow.Hidden = False

So I have deleted the protect/unprotect code for now. Would really like to get this to work without the flicker?
Any suggestions greatly appreciated

BTW - I have picked up all of my code from the internet, am a total novice so need layman explanations )

Thanks in advance

Private Sub Worksheet_Calculate()
Dim myresult As String
Dim MyResult1 As String
Dim MyResult2 As String
Application.ScreenUpdating = False
Application.EnableEvents = False
 
Rows("1:" & Worksheets("Q U O T E").UsedRange.Rows.Count).EntireRow.Hidden = False
myresult = Worksheets("Q U O T E").Cells(99, 1).Value 'Controls'
MyResult1 = Worksheets("Q U O T E").Cells(64, 1).Value 'Valve Chamber'

''''''''''''''''''''''''''''''''''''''''''''''''''
Select Case MyResult1
Case "", "None", "0"
Rows("64:83").EntireRow.Hidden = True
Rows("156:156").EntireRow.Hidden = True
End Select
Select Case myresult
Case "", "None", "0"
Rows("99:114").EntireRow.Hidden = True
End Select
Application.EnableEvents = True
Application.ScreenUpdating = True

End Sub