Still Lurking at TextBox calculations Problem... Plz Help:(

[Plucky]

Dear mentors,

This should happen only once when i add something in texbox. But it pluses again values of textbox1.text + textbox2 when i modify a record.

Private Sub textbox2_KeyPress(KeyAscii As Integer)  
           If keyascii = 13 then  
                   textbox3= val(textbox1.text) + val (textbox2.text)  
            End IF
End IF

I want: the Result remain stable, if i add something in textbox1 it add in Result and when i delete any value which is already in textbox 1 or 2 it effects on result during modification.

plz help rapid..
thanx inadvance