In the windows version, the spell check option is grayed out and not available. I have tried to find GTK spell check for windows but none seems available. Are there any other solutions?

Pygtk spell check was not available when I first added this feature last year. I do not know if the situation has changed. As far as I know, spell check is not available for the windows version of KeepNote. Maybe someday, I'll switch to a spell check that is more cross platform.

If it helps, I believe the Windows version of Pidgin relies on Aspell (GNU) for spell check implementation. You're probably familiar with it but it's worth a look if not: http://aspell.net/

(I'm no programmer so if this is not feasible you have my apologies :))