How can you install a clean copy of Windows 200 or XP without reformatting the hard drive?How can you install a clean copy of Windows 2000 or XP without reformatting the hard drive?If your system has enough free disk space for a second operating system, you can reinstall Win 2000 or XP from scratch without wiping out the entire drive.Clean up the drive and make a backup. Gather the installation disks and files for your operating system, antivirus software and applications.Download the latest updates and save them to a diskette or CD.Use an NTFS-capable partition management utility (such as\u00a0BootIt-NG https:\/\/www.terabyteunlimited.com\/bootitng.html)\u00a0to split an existing disk partition to create fresh unformatted disk space on your computer. Follow the instructions on your partition-manager software to mark the new partition active.Shut down the computer and reboot from a write-protected operating system installation disk. Install a clean copy of the operating system.After installing it, test to ensure you successfully can restart the system to boot the new clean version of the operating system. Install your operating system updates, anti-virus software and virus definitions.Once you are comfortable that the new installation starts correctly, you can erase the Windows (or WINNT) directory from the old boot partition. Then reinstall your application software.