I am not sure if you can do it through Fedora (you prbally can though), but you can go to the following
Start > Settings > Control Panel > Administrive Tools > Computer Management > Disk mananegment
Right click the partitions you want to delete and delete them. After that is done you will need to fix your MBR. To do this you need your Windows installation disk. Boot it up and go into the recovery console and type fixmbr.