Vista does not recognize my external HDD

Hello,

My Dell Inspiron with Vista Home Basic laptop doesn't recognize my portable western digital 500 gb external hard disk.
1, the lights in my external hdd blink and the disk seems to be working when I touch it,
2, the hdd shows in my device manager and it says the drivers are up-to-date and is working properly
3, the hdd doesn't show up in disk management
4, every time I connect, there is a message saying the usb device is not recognized.
5, the hdd works when I connect it to another comp (my desktop with windows 7)
Please help