where would unseen mail be hiding? and what is the "other" that is taking up space

Hi,

Mail gave me a message that it "had to repair" so I clicked "repair" – then it looked like 800 emails came in (according to the bar) – when complete I went to mail to delete them, but I do not see them. Where are they and how do I get rid of them?

Also, I keep getting a message that the start-up disc is full – yet I barely have anything on here. The storage shows all the way full and it is all "other." Any idea how to get rid of this?

I did the software update and ... I also cannot get my photos. It says to repair, I click it ... and nothing happens.

Help would be soooo appreciated – I am getting soooo frustrated and ... not really happy about mac anymore, I keep having sooo many issues and my laptop has become very unreliable (yet ... I don't have alot of things I have stored on it).

Mahalo for any assistance!!

Adaire