Email help needed


New Email
I just got a new PC and need help setting up my email . It has windows 7 with IE 9 (i believe) .

I run 2 emails yahoo (shared account) and a gmail account (private account) . I used to be able to click on an email link on Craigslist and it would open and send from my gmail acoount . How do i do that again ? It says "default mail client is not properly installed ". I think i used to run outlook express for my private account but i checked it on gmail directly . How can i set this up again ?