XP takes minutes to boot-up

I've had XP for quite some time now, download SP2 when it first came out and
had no problems until last Sunday. I turned my computer on and after the XP
logo extinguished it took approximately 5-7 minutes before the user's page
loaded up. Once up and running the computer is flawless. I swapped out
video cards and no change. Last OCT, my other computer also operating XP
failed. So, I used that hard drive in my slow boot computer. It booted up
with no problems. I downloaded the latest updates for XP and updated some
other programs like Nero. On the next boot up it took 5-7 minutes as
explained above. Any ideas...I haven't tried unistalling the XP updates (it
makes sense that it's my problem), but how could it be?