Pleas help me shorten this code snippet

[Joshua291]

I am programing a Playfair Cipher and im trying to shorten this code. PLEASE HELP.

If tbLetter1.Text = "I" Then tbLetter1.Text = "I/J"
        If tbLetter2.Text = "I" Then tbLetter2.Text = "I/J"
        If tbLetter3.Text = "I" Then tbLetter3.Text = "I/J"
        If tbLetter4.Text = "I" Then tbLetter4.Text = "I/J"
        If tbLetter5.Text = "I" Then tbLetter5.Text = "I/J"
        If tbLetter6.Text = "I" Then tbLetter6.Text = "I/J"
        If tbLetter7.Text = "I" Then tbLetter7.Text = "I/J"
        If tbLetter8.Text = "I" Then tbLetter8.Text = "I/J"
        If tbLetter9.Text = "I" Then tbLetter9.Text = "I/J"
        If tbLetter10.Text = "I" Then tbLetter10.Text = "I/J"
        If tbLetter11.Text = "I" Then tbLetter11.Text = "I/J"
        If tbLetter12.Text = "I" Then tbLetter12.Text = "I/J"
        If tbLetter13.Text = "I" Then tbLetter13.Text = "I/J"
        If tbLetter14.Text = "I" Then tbLetter14.Text = "I/J"
        If tbLetter15.Text = "I" Then tbLetter15.Text = "I/J"
        If tbLetter16.Text = "I" Then tbLetter16.Text = "I/J"
        If tbLetter17.Text = "I" Then tbLetter17.Text = "I/J"
        If tbLetter18.Text = "I" Then tbLetter18.Text = "I/J"
        If tbLetter19.Text = "I" Then tbLetter19.Text = "I/J"
        If tbLetter20.Text = "I" Then tbLetter20.Text = "I/J"
        If tbLetter21.Text = "I" Then tbLetter21.Text = "I/J"
        If tbLetter22.Text = "I" Then tbLetter22.Text = "I/J"
        If tbLetter23.Text = "I" Then tbLetter23.Text = "I/J"
        If tbLetter24.Text = "I" Then tbLetter24.Text = "I/J"
        If tbLetter25.Text = "I" Then tbLetter25.Text = "I/J"