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 Cumulative 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 simply a new version of the Normsdist function that is available in earlier versions of Excel.
The format of the function is :
Where the function arguments are listed in the table below :
z    The value at which you want to evaluate the function  
cumulative   
A logical argument which denotes the type of distribution to be used:

The above chart on the right shows the Standard Normal Probability Density Function.
If you want to calculate the value of this function at x = 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 Cumulative Normal Distribution Function.
If you want to calculate the value of this function at x = 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 can be found 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 the supplied argument is not recognised as a numeric value 