I was seriously disappointed trying to find working videos for Queen Seon Duk on mysoju. Luckily, I found http://www.dramafever.com
where you can watch for free but with (annoying) ads, or pay $5 a month to get rid of the ads.
After watching the Dockers ad with men not wearing pants about 100 times, I forked over the $5. Anyway, dramafever has great quality video, no ads, reliable, comment threads, etc... Excellent selection for a newbie to kdrama like me. Old stuff and new.
When my semester ends in a few weeks, I am diving head first into one or two new dramas. I can't wait!
(Not affiliated with dramafever in anyway, just a satisfied customer!)