SLOW response in Outlook Express

Upon rebooting, and subsequent first attempt at either opening an existing message or perhaps wishing to write a new one, the response time is abysmally slow, like, at least a few minutes in length before the applicable window will open. After the first attempt, it gets markedly better, but the first one of the day takes forever.

Is there something I can do to remedy this? This started happening about a year ago. Before that, it was fine.

I am running on XP with Norton Anti-Virus, and regularly check for Spyware with Ad-Aware (free version).

Thank-you for your help in this regard.