I have an old Thinkpad X60 that I'd like to wipe clean and rebuild. Seeing as this machine doesn't have an optical drive, what's the easiest way of installing Windows XP?

I have an external USB hard drive available. Would it be possible to run the install from that instead? Otherwise, what options do I have?

Edit: assuming we're using a USB mass storage device...

Is there a BIOS setting that I would need to change, or will it configure itself automatically? Would the USB drive need to be configured in any special manner, or would simply having a copy of the Windows CD files in a directory there be sufficient?

Since the first couple answers that came in were basically "yes", I guess I didn't phrase my question correctly. I'm asking for detailed instructions on how to do this, not just a sanity check that I'm headed in the right direction. Thanks!