Cannot ri on windows 8

Hi all,

I try to do some ri on windows 8. Here are results:

ruby 2.0.0p451 (2014-02-24) [x64-mingw32]

C:\Users\alex>ri

Enter the method name you want to look up.
You can use tab to autocomplete.
Enter a blank line to exit.

ri GC
Nothing known about .ri GC

ri GC.start
Nothing known about ri GC

C:\Users\alex>ri start
Nothing known about .start

C:\Users\alex>

I wonder why ri fails?

Thanks,

If you installed by RubyInstaller will not work. If you compiled Ruby
from scratch, and installed ri will work. The fact is that if you
installed by RubyInstaller you have a *.chm file with all the
documentation you need, search there.

Thanks. Under the doc folder, I have a *.chw and other documents.

Yes *.chw that is.