Cannot Boot Without External HD Plugged In

I’m running Vista Home Premium, and experience problems every time I tr
to boot my PC without an external USB hard disk plugged in and running
This has been going on ever since I first used the external hard dis
with my PC. I have ignored the problem and just kept the drive plugge
in at all times, but recently I’ve had to lend the drive out and a
forced to wait about 10-15 minutes every time turn on my PC. I can’
boot Vista without accessing the boot menu by pressing F8 and tellin
the computer to boot the system from the C drive. For some reason ther
is an extremely long delay between the time I press F8, and when th
menu comes up. Once the system boots up, everything runs fine but th
delay is extremely annoying and I don’t want to always have to b
running the hard disk, and wasting electricity for no purpose other tha
booting up my PC. Has anyone else experienced this problem? An
suggestions?

Thanks,
Ada