Live update upon boot

Every time I log into my Win-XP laptop I get a warning from Windows that my virus protection is out of date. When I open NIS it also tells me that virus definitions are out of date, offering a big "FIX IT" button. I initiate the update and it proceeds without problems. My boot time protection was set at NORMAL (which I just switched to AGESSIVE) and both automatic live updates and pulse updates were ON. I suppose this is  because live update is not among the first processes started when the machine boots, I don't know how long it takes before NIS decides to check for updates and I could not find any way to speed this up. When the machine is on for longer periods, automatic live update works fine. Any suggestions?