Unfortunately there isn't a way to easily convert a partition from NTFS back to a FAT based one. Some applications such as Partition Magic *may* have an option, but I'd make sure you have a backup of all your data before hand.
 
If programs like PM don't have that feature, then you will need to wipe the hard disk and reinstall everything, formatting the parition as FAT32 before installing Windows 2000 again.
 
Can you not take your laptop into a shop and ask if they can install the software onto it in order to test if it actually does work or not? If they think they will make the sale if it works might encourage them to go this little extra distance.

I've been running Win2000 NTFS on 3 different laptops for the last year and 3/4s and I've had no trouble with any of the mp3 players I've used. My regular player is MusicMatch but I also use Winamp with some degree of regularity. I've experiemented with several others as well and they've all worked perfect.

i think he's refering to Hardware MP3 player? so that might be the problem he's getting that it can't read ntfs file system. The only options would probably to re-install win2k and this time install it with fat32 instead of NTFS, otherwise, invest in an external harddrive and format that new drive as fat32 and copy those mp3's onto that drive.

no, you can resize your ntfs partition (do a search for "Partition Resizer", its free and resizes ntfs partitions) decrease the size of ur current partition, then in ur Disk Administrator snap-in, create another partition, format it as FAT32, store your mp3's on that partition, good luck ..
-neural