Tomsan, what I would do in your case is remove the entire partition table, and start over. This will result in the loss of all data on your disc, however.

This link will bring you to a step-by-step tutorial on how to delete your partition table - it also has links to all the software you need (actually, that will fit on one floppy). On the bottom of the page is a link that will bring you to another page that (again, step by step) will guide you through creating partitions, both fat16 (up to 2GB) and fat32 (2GB++)

Good luck to you. One word of advise: if you're new to this, do things slowly. Make sure you have read all the pages before you continue, so you know what to expect. Printing out the pages before you continue won't hurt. Like I said, good luck.