If you are trying to access the disk in My computer, it will have to be set up first in your BIOS. I believe you when you say it's properly connected and all, but did you check the "jumper" settings? If this Fujitsu drive was the only drive in your windows xp comp, you will need to be careful that you set the jumper on your new harddrive as "master" (not "stand-alone master") and the Fujitsu as "slave. Also, they should both be connected throught the same cable to the same IDE bus on your motherboard.
Also, if the fujitsu is in FAT32 file system for any reason, your Vista machine won't read it. you would need to format it (loose ALL data) through the disk manager.
Hope this helps. Feel free to email me if you can't get it from here.
sewellp@yahoo.com
Patrick Sewell, January 2008