Tell Program To Go Back To A Private Sub?

I have a code for a tic-tac-toe game, where there's basically 3 private subs. There's a sub called "userturn" that handles the button clicks on the board. The next sub is "compturn" which controls where the computer moves. The last one is "checkforwin" which does what it says.

Here's my problem:

At the end of the "userturn" sub, I have a line that says, "compturn()" to tell it to go to the compturn sub. That sub is executed correctly, but when I try to add the line, "userturn()" to go back to the userturn sub, I get this error[code]...