Ext USB drive not in My Computer

I have searched on Google extensively. I have a relatively generic USB external hard drive. I have Windows XP Home, free USB ports, etc. I have two SATA hard drives and two IDE cd/dvd burners. When I plug my ext hard drive into my laptop (also Windows XP Home) it is recognized immediately. When I plug into my home computer the icons appear in the system tray and I can safely remove the hardware but it never shows up in My Computer. After searching on Google I tried to use the Disk Manager in Admin Tools in Control Panel but the drive isn't listed. It's formatted properlly as I can see and manipulate anything on the laptop. Both the laptop and the home computer have all available Windows XP updates.

 

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