Reverse your test:
MsgBox("Do you want to clear all?", MsgBoxStyle.YesNo, "Clear the textboxes!")
If MsgBoxResult.Yes Then
TB1.Text = "0"
TB2.Text = "0"
TB3.Text = "0"
TB4.Text = "0"
TB5.Text = "0"
L1.Text = "0"
L2.Text = "0"
L3.Text = "0"
L4.Text = "0"
L5.Text = "0"
SCORE.Text = "0"
Label10.Text = "Here"
End If
But please, start using .NET classes instead of outdated VB6 ones:
MessageBox Class (System.Windows.Forms)[
^]