Not able to find the ruby file in command prompt with ruby and rails

Why am i not able to run win_fetch_cacerts.rb ruby file thats there in my desktop? :\

C:\Users\punitha\aggregator>ruby "%USERPROFILE%\Desktop\win_fetch_cacerts.rb"
ruby: No such file or directory -- C:/Users/punitha/Desktop/win_fetch_cacerts.rb
(LoadError)

What happens if you go to the directory and run ruby win_fetch_cacerts.rb?

What happens if you run ruby c:/Users/punitha/Desktop/win_fetch_cacerts.rb?

What happens if you try an run another ruby file in a similar way?

Or to put it another way, what is it about the attempt to run the file that it does not like?

Colin