That is very odd. I have another idea. It is kind of long, but it is worth a shot.
First, run Windows Update. Go to http://update.microsoft.com
. Install all the updates it finds. It may ask to restart, but do not do so yet.
Now, go into device manager and uninstall the driver for the MP3 player like you did before. Then unplug the MP3 player, but do not plug it back in yet.
Reboot, and right before the XP screen is supposed to appear, press and hold F8 until you get a boot menu. Then, select Safe Mode with networking.
Once you log on, plug your MP3 player in. Hopefully, it will not recognize it, and it will pop up with the Add New Hardware Wizard. If it doesn't, go into the device manager and click Install.
When you get the add new hardware wizard, say you are connected to the internet (only if you are). Then, on the next screen, select Install the Driver from a specific location.
On the next screen, un-check the box labeled Search Removable Media and put a check in the box labeled Include this Location in the Search. For the location, choose "C:\WINDOWS\inf\" (if the "inf" folder does not appear, go into Start > Settings > Control Panel > Folder Options > View > Show Hidden Files and Folders
) Then, click next. It should find the driver.
If it doesn't, un-check the box labeled Include this Location in the Search, and put a check in the box labeled Search Removable Media. Now, pop in the CD that came with the MP3 Player. Have it search that.
Once it has found the driver, reboot and go back in normally. If it boots up in safe mode by default, press F8 in the same way as before, and select Start Windows Normally. Now plug in your MP3 Player and see if Windows Explorer recognizes it.
If those steps don't work, check if it is recognized in Windows Media Player as a portable media device. You may need to use that to transfer music. Note that sometimes it requires Windows Media Player 10, so you might have to upgrade it.