I try to e mail on craigslist and my computer won't let me it keeps saying that I don't have 'stmp' or something like that... how do I fix it to where I can e mail on craigslist?

Tabby,
I assume that you are responding to something on Craigslist, by clicking the link? If so, then the link will bring up your default email program (Outlook Express, maybe?) and try to email the person.
If you only use web-based email (Yahoo, Gmail, MSN, Hotmail, etc), then you need to right-click the link on the ad, then choose "copy shortcut", log into your webmail account, create a new message, and "paste" in the TO: field of the new email.
If you do have Outlook Express or another email program, you need to call your internet provider to have them walk you through setting up the SMTP (Simple Mail Transfer Protocol) server settings... by the way, that's just the Outgoing mail setting :)