Spell check should work just fine. Go to Tools>Options>Advanced> Under the browsing section see that "Check my spelling as I type" is ticked.
Sorry I am unable to help with the icon change.
I want to change the regular Firefox Icon in the Browser window to one of my own, and have tried following the instructions on the Firefox help :Tips and Tricks page here http://www.mozilla.org/support/firefox/tips#app_icon
but when do as instructed nothing happens. Does anybody know another way of changing it. I am using Firefox 2, also whilst typing this message that the spellchecker duz not pic up mi speling erors. Do i need to enable it or shud it workby defalt?
Hope somebody out there can help.