Windows wants and expects to be the first (and only) OS on that drive and isn't recognizing linux partitions.
The best solution would be to back up your data (/home) from Fedora and then either use gparted live http://gparted.sourceforge.net/livecd.php
to remove all your partitions or use dban http://dban.sourceforge.net/
to completely wipe your drive. Either way, start with a clean slate and then set Windows as your first partition, followed by Fedora on the remainder of the drive and allow grub to set up the dual boot. While you're at it, I'd also set a FAT32 partition to swap data between Windows and Fedora.
With the upcoming release of Fedora7, this would be an excellent time to make the change and pick up the very latest that Fedora has.