Help with If not-statement

Hi,

I'm writing a macro at work to help a few colleagues (and, occasionally, myself) out. The main function of the program works flawlessly, yet one thing still bothers me.

After that I've declared all my variables I want the macro to check if the rows A:A and B:B are empty, and if they are not, to display a message which says that the macro will replace all current information in the A:A and B:B cells and ask whether the user wants to call the macro or not. The problem is that the message declaring that the cell values in A:A and B:B will be replaced pops up even if the cells are seemingly empty.

I've tried to rewrite the code in a couple of different ways. Here's current version of the code that's annoying me:

Dim blablabla
[...]
Empty1 = IsEmpty(Range("A:A"))
Empty2 = IsEmpty(Range("B:B"))
If Not Empty1 = True Or Empty = True Then
Assert = "All information in the columns A and B will be replaced." & vbNewLine & vbNewLine
Assert = Assert & "Do you still want to continue?"
Ans1 = MsgBox(Assert, vbYesNo)
If Ans1 = vbNo Then Exit Sub
End If

Range("A:A").Clear
Range("B:B").Clear

[...]

Does anyone have any ideas on how to solve this and where I might have lost my way?

Cheers,