Option Explicit
Sub test()
Dim t As String
t = "FORWARD BLOCKING VALVE (Hydrau.)"
'en respectant la casse
If InStr(t, "blocking") > 0 Then MsgBox "trouvé..."
'quelque soit la casse
If InStr(t, UCase("blocking")) > 0 Then MsgBox "trouvé..."
'ou ceci
If InStr(1, t, "blocking", 1) > 0 Then MsgBox "trouvé..."
End Sub