Mail app wont open since 10.5.6 update

I updated yesterday from 10.4 to 10.5.6 to get ilife. Since then, mail mail app wont open. I click, one bounce and nothing! When I go to restart my G5 it shows mail as being open. I can open a new viewer from the upper tool bar, this will shoe me my folders, but wont open, and nothing appears in my inbox. I can see all my messages and send and receive via web on mobile me. Ive tried syncing... seems the issue is mail not opening to begin with. I getting a wee bit desperate!