vb Code:
Select Case Form2.CheckBox18.Checked
Case True
lines(foundIndex) = Regex.Replace(lines(foundIndex), "(?<=" & "sIntroSequence" & "=)\d+", "BGS_LOGO.BIK") 'WRITE "BGS_LOGO.BIK"
IO.File.WriteAllLines("C:\test.txt"), lines)
Case False
lines(foundIndex) = Regex.Replace(lines(foundIndex), "(?<=" & "sIntroSequence" & "=)\d+", "") 'REMOVE TEXT (IF ANY PRESENT)
IO.File.WriteAllLines("C:\test.txt"), lines)
End Select
You are checking the wrong property in your Select Case statement
One of the earlier posters resolved your problem already.
Sorry you weren't paying attention