Randy, thank you so much for your help. By the way, how do I set up Bios to do what you advised me to do below. I tried and failed. I have no idea what to choose (IDE or something else). I have Windows XP. Below is your advice last time.

in the bios setup set the internal harddisk to be the primary storage device and the external to be as the slave one...

if you are using primary ATA disk...try changing the jumper positions..

thankyou

Computers & Internet - Western Digital - 500GB My Book World Edition 500 GB Hard Drive