Windows XP boot loop with external drive attached

i'm running windows xp and have all the service packs. the problem i am having is occurring on both my gateway tower pc and my dell laptop. after attaching a 320 gb external hard drive to either pc (using a firewire connection to the gateway pc and a firewire to mini-usb on the dell laptop, i find that the computers recognize the attachment of the drive when the attachment is done after the machines are running but, if i try to restart the units when the drive is attached and turned on, i get into a boot loop when windows xp starts to fire up. my only option is to turn off the power, disconnect the drive and restart from scratch. when i do this, i get a message that the shutdown was not done "correctly" and i simply indicate to restart "normally"...i don't need to restart in "safe" mode. once restarted, i can reconnect the drive and turn it on and everything works fine. what do i need to do to get the pc's to restart with the drive attached? any help would be much appreciated....and i'm a little more than a novice with this stuff...but no expert by any means........thanks ps. the drive is a western electric IEDE type