Vista not recognizing hard disk in My Computer, but available in Disk Manager

After installing Vista I thought I can use something new in Windows. But I landed into a new problem. I have a HP D530 CMT laptop. It came with Windows XP. It was working quiet fine. I upgrade to Vista by checking through Upgrade Advisor. It told that everything is proper and I can use Vista. I have a additional 500 Sata external hard drive installed. It is not visible in My Computer. While I checked it in Device Manager and it shows it is installed. My internal drive which is a 250GB Seagate hard disk is available. I checked in Disk Management. The hard drive is available. But there is no driver or partition visible in My Computer.

What you can see in Disk Management. Click on the 500Gb external drive. If the status does not show healthy then you cannot access it until you format it. If you are having data in that, then formatting will wipe out everything from that. You can try using some other computer on which the driver will be connected for the first time. And if it is entirely new then just format it through Disk Management. That's all it will appear in My Computer.