Xp SP1 causing boot to hang for 30 minutes!?

[hnt]

I just updated my WinXP Pro laptop with SP1 and now when I reboot the system hangs for about 28-30 minutes! How do I determine the cause of the hang?

It hangs after I login and before (most of) the icons display their images... The taskbar (including the time) is blank and does not respond.

Thanks

[hnt]

It turns out that the cuplrit was Trend-Micro's PC-Cillin service...
After disabling it, the machine boots normal!