Go Back a Page?
 

When the user clicks next from the previous page, I have a pre-function on the next page to test if a program is running. If it turns out that it is running, I want to send the user back to the page which they came from. I have all the code in place to see if the program is running, I just can't find an example of how to send the user back. I might have to send them back 2 pages in another case.

Thanks
Joe

You can try this one:

http://nsis.sourceforge.net/Go_to_a_NSIS_page

or, alternatively, why not put that check in the post function of the page the user is leaving - and if that check shows that the program is still running, call Abort to prevent the page from changing in the first place ?