Hi Doublejoy
I assume that you are trying to average data in cells C2:H2 but ignore the zero in H2 ie average the five positive numbers. Try this array formula
=average(if(C2:H2<>0,C2:H2,false)). As this is an array formula to enter it you must hit ctrl, shift and enter at the same time, this must be done every time you alter the formula. You will know if it has been entered correctly as excel will automatically insert a "squiggle" at the start and end of the formula.
Hope that helps.
Rod