Dmitry-

Set your system bios to boot from the CD drive, make sure that your windows XP CD is in the drive, boot to the system CD, once in the setup, you will be asked where you want to install XP and your system partitions should be displayed. Delete the old partition and format a new NTFS partition. It's very easy!

Good luck!

Becki

PS-Be sure that all information that you want to keep has been copied off the drive prior to performing the above steps.