If you are using Internet Explorer my recommendation for a spell checker is to install the free one at
http://www.iespell.com.
I've been testing it for about a month and it works better and faster than the integrated spellchecker in the old Forum. It's just as easy to use and has more features.
Another
big advantage for this low-budget site is that it is free. I had to pay spellchecker.net $150/year

for the one on the old Forum.