"However" is like "but," except that it's meant to be used for the start of a new sentence, instead of connecting a compound sentence.
"This is a terrible situation, but it's best we all remain calm."
"This is a terrible situation. However, it's best we all remain calm."
You can use either a semicolon or a comma before "however" depending on the context. Use a semicolon to separate two independent clauses, and use a comma when "however" is used as a conjunctive adverb to connect two sentences.
I don't like writing, however, I am good at it.
just like BUT ..
instead of but, use however.
However she wanted to.
Yes, you should typically use a comma before and after "however" when it is used as an interrupter in a sentence to indicate a contrast. For example: "I wanted to go to the party, however, I was too tired."
I like vanilla ice cream; however, I love chocolate better.
Ben planned on going to the zoo; however, he didn't have a car and therefore, couldn't go.
You can use the word however it is proper to do so.However great the difficulty, they managed to persevere and succeed.I think he's a good guy; however, I could be mistaken.(It can also be used to connect separate sentences.)The device failed to work. However, most of the design proved reliable.
He was not, however, the first to use the frame story.
Can think of something like-however this argument is looked at... and you get some more ideas (:
WikiAnswers is a great resource; however, it is not capable of answering everyone's questions.