Most E-mail servers have these features and they should be used, because we know it takes way too much time to look at the Dictionary anymore. Nothing makes a worse impression than poor grammar and misspelled words. A poorly written, or abbreviated E-mail sends the message that the sender didn't care enough about the recipient to bother wasting any time on him or her. He who hesitates is not lost, check it again. If so, it never hurts to also print out the letter on good quality stationery and mail it as well as E-mailing it.
Many people make the mistake of CC'ing too many people and letting the other names show.
If not, some of the recipients will get upset because their E-mail addresses have been exposed to others without their consent. And never ever misspell a person's name if it can be avoided. You can also setup Letterheads on your email just like on real life stationary. If your computer has been acting strangely, odds are it's been infected with some kind of computer virus. If you send an E-mail, you will also send the virus and this could mess up the recipient's computer as well.