There was a time that I could spell reasonably well. We won't go down the grammar and punctuation road. In recent years my spelling has become worse and I have resorted to using a spell checker. This one was recommended by a Cruisemates poster a few years ago and I installed it and have been using it. I'm sorry but I forget who it was. It works quite well and is easier than writing in Word or other text editor and then cutting and posting. You may wish to give it a try.
Remember, it only checks spelling, not grammar or punctuation but it helps. You also have to remember to hit the "abc" button in the IE tool bar to run it. (I've not done that on a number of occasions.)
It is free and as of the last time I downloaded it, it was virus, malware and adware free. I make no other endorsements of the product other than the fact I use it and have been happy with it.
Here is the link.
You can just click "download" on the left side menus.