I got a new 3800+ HP desktop computer and want to use it with the external
80 GB HD which I have used before with a custom built CPU which I used
before.

When I boot up with the HP new CPU and have the external disk connected, the
bootup takes forever. It stops and continues immediately to desktop once I
disconnect the external disk.

The same is true for shutdown. It just sits there and does not shut down
until I disconnect the external disk, then shutdown is immediate.

Another thing. Once I start up (and have the external disk disconnected to
get to the desktop) and then connect it, I cannot see the external HD under
Explore.

I have to go to the Administrative tools then Diskmanagement and let it find
the external disk. Once it does. I can see it in the Explore position.

What causes this strange behavior? The external enclosure is fine. I took it
to the computer shop, where I bought it months ago and they even connected
it to their running computer and it was immediately seen.

I am totally puzzled at this time.