Why won't my 40GB Fat32 hard drive work in Windows XP?

It was originally the internal disk in an old imac, but now I have it in a USB2.0 case. It has been formatted as FAT32 by Disk Utility in Leopard. It is an external drive. It works fine on a Mac. I have tested it on several different PCs running XP.

I thought that windows could use a FAT32 drive larger than 32GB, but that it just couldn’t create one. If that is incorrect, is there a way to make it work, or to even make a partition that’s less than 32GB work?

Thanks.