The Standard Normal Distribution is a simplified version of the Normal Distribution Function which arises when the mean of the distribution is 0 and the standard deviation is 1.
Therefore, the Excel Norm.S.Dist function is the same as the Excel Norm.Dist function with the mean and standard_dev arguments set to 0 and 1 respectively.
The Excel NORM.S.DIST function calculates the Standard Normal Distribution Function for a supplied value.
The Norm.S.Dist function is new in Excel 2010 and so is not available in earlier versions of Excel. However, the function is an updated version of the Normsdist function, which is available in earlier versions of Excel.
The syntax of the Norm.S.Dist function is:
Where the function arguments are as follows:
z    The value at which you want to evaluate the function.  
cumulative    A logical argument that denotes the type of distribution to be returned:

The above chart on the right shows the Standard Normal Density Function.
If you want to calculate the value of this function at z = 0.5, this can be done using the Excel Norm.S.Dist function, as follows:
This gives the result 0.352065327.
The above chart on the right shows the Standard Normal Cumulative Distribution Function.
If you want to calculate the value of this function at z = 0.8, this can be done using the Excel Norm.S.Dist function, as follows:
This gives the result 0.788144601.
Further information and examples of the Excel Norm.S.Dist function are provided on the Microsoft Office website.
If you get an error from the Excel Norm.S.Dist function this is likely to be the #VALUE! error:
#VALUE!    Occurs if any of the supplied arguments are nonnumeric. 