Fdisk is a hard drive partitioning program. Its best to have it either on a bootable floppy or cd-rom. Once fdisk is run the hard drive will be erased. You will need to reinstall your operating system. When you boot into dos, type fdisk.exe in the directory where fdisk.exe is and you will be start fdisk. Then pick the hard drive you want to partition and then execute the partitioning. Make sure pick the correct hard drive because it will get erased.