Ok, I seem to have this same problem. I reinstalled windows xp and my 40 GB hard drive works fine but my 250 GB hard drive doesn't show up in "my computer" . I've read what all you have said and I went to disk management and it won't allow me to right click on the hard drive to change the letter. The only thing it says is to Delete partition. :eek:
The second hard drives name "music" shows up but no letter. Like the others in this thread I can see the second hard drive in Bios and in disk management and I tried to update the drivers but it says that I have the latest ones...

Thanks for any help that you might be able to give me in this.

Let me see if I understand this. The 250GB drive is labeled "music". It appears in disk management, but with no drive letter assigned. The assign drive letter is greyed out.

It sounds like it may be hidden. You will need to use a partitioning utility to "unhide" it, such as Norton Partition Magic. Here is a link that details the same problem.

Mod's Note. Generally its not a good idea to piggy back on someone else's thread. It can confuse things. So I've moved your question to its own thread