>A form has a checkbox that says: "Stop processing".
>
>The form has timers that run code.
>
>The problem is that I can only get access to the checkbox (to check it) when there is a gap. That is when the code has stopped running and the next timer event has not yet started.
>
>I would like to be able to "Stop processing" at any time. Any thoughts on how this can be accomplished?

A DOEVENTS at certain points in the timer code? It'll probably make it a tad slower, but should give the code a chance to process user input.