Thunderbird won't mind me!

I installed Thunderbird a few days ago, 'tis working ok, but it will not obey my orders! I have tried to change the font two different ways, but when I write another email it reverts to the original Variable Width. I tried to send as both Text and html and each time it asks again. I click Sent and receive no information, although I have sent out a lot of email. I saved something to Draft, but it was not there when I opened. I unclicked Let Messages use other Font, which did not change anything, at least that I noticed. Gee, if this continues I am going to start tearing out my hai_, Whoops, I don't have any to tear out. But I am not really worried as I know someone will be kind enough to tell me how to make change in settings stick. Thanks, Woody