OK, I will use the previous code with a few mods/additions to allow for you to change the 'you' to 'me'.

Dim strPos as Integer

' The following line will search for 'you' in the textbox and return
' the position in the textbox
strPos = Instr(txtInfo.Text, "you")

' If the position returned is greater than 0 then we have
' found 'you' so now replace it with 'me'.
If strPos > 0 Then
' The Mid function returns a string from within another string
' based on the start position of 1 and the length of strPos.
' strPos being the start of the word 'you'.
' If you don't specify a length then it is considered to be the
' length of the remaining text.
txtInfo.Text = Mid(txtInfo.Text, 1, strPos - 1) & "me" & _
Mid(txtInfo.Text, strPos+3)
End If

I hope this helps.