I vote new computer.
lol, you kinda walked into that one.
There is a tool in XP Pro and Media that can help with this. I am not sure if it's in XP home, so if thats what you got, it may or may not show up.
Anyway, go to start->run and in the box type "compmgmt.msc /s"
That should open up a window.
Click on "Disk Managment"
From there you will see two sections.
The top one is of drives your system sees and you can get to via My Computer
The bottom half is where all physical drives it can see. See if you can find it there. If you can, right click and click the entry on drive letters/paths. Assign it a drive letter.
If that doesn't fix it, you may have a driver problem.
If you are updating the driver and letting the OS search for the drivers, you should have no problem and I can't really help you any farther then this.