Originally Posted by slim chillingsworth
You can't boot from an external hard drive because your computer doesn't recognize a usb or firewire connection unless it has drivers installed on its own internal hard drive.
As already said - wrong. Depending on the manufacturer I think Dell lets you hit F2 (something mentioned that too I think). Select the USB ports as bootable option before IDE and all the other crap and you are good. Leave your bios menu, hit F12 for dell, select CD/DVD-Rom and boot from cd, install OS on external hdd and you are good to go.
Have to deal with similar crap at work every day....