Hyphens and semi-colons

[Conspiracy.]

I don't understand when to use a hyphen or a semi-colon :| I've googled it and I still don't get it.

Could you give me a few examples where you'd use a semi-colon and where you wouldn't?

Also, how would I know when a word needs a hyphen? does bi-sexual? does ex-girlfriend? does semi-colon? LOL, does hedge-clippers? does bad-mannered? :|

[Jazz]

U-turn, X-ray
re-form - reform


Jazz finished cooking her pie; she spent £1.99 on it
Jazz's Age: 17

hedge clippers and bad mannered don't I wouldnt of thought.

[Lee]

Have a read of: http://theoatmeal.com/comics/semicolon and http://www.grammarmudge.cityslide.co...26348/2805.htm

Hope I helped

[Conspiracy.]

Thanks I kind of get it now

[Samantha]

A semi colon and hyphen link.

So say you are talking about something and an addictional detail could be added like how @Maggots described it .