thanks for the help guys, but i've found an alternative way to format my linux drive.
By the way i try to boot into dos with the dos cd rom(http://www.doscdrom.com
) method but it still fail to boot into dos, anyway..
For those who do not have diskette drive to boot into dos or fdisk can use my method, you need to have an extra harddisk in order to format the drive that contain linux, for example my linux has been installed in C: hard disk.
Its very straight forward, what you need to do is set your second hard disk example D: drive as the main drive and boot window xp disc into it. This method allow you to boot into the window set up.
Once your in the setup you will be able see your C: drive, don't worry if it does not display the linux parition i think window can`t read that parition, anyway just select that drive and format with FAT.
After formatting simply reboot, set your C: drive back as the main drive and you can reinstall window XP back from here. Hope you get the idea.