this question was actually asked in a previous post and answered by Juan Pablo. you want to use an array function. for example if cells A1:A4 house the values 0,1,2,3, you need to enter the following formula:
=MIN(IF(J22:J25,J22:J25))
and instead of pressing enter when completed with the formula, you need to press shift+control+enter, and the cell that contains the formula will return the smallest non-zero number, in this case, 1. after entering your formula, your formula should have '{}' brackets around it
HTH
kevin