If you plan on using Windows ® as well as Linux by dual-booting (being able to access either system on the same computer), please note that it is easier to install Windows ® before Linux. If Windows ® is already set up on your system, and you have never installed Linux before, DrakX — Mandriva Linux's installation program — will have to re-size your Windows ® partition. This operation can be harmful to your data. Therefore, you must perform the following steps before proceeding:
Run chkdsk on your Windows ® computer (also called scandisk on some non- NT systems, such as Windows ® 9x). The resizing program can detect some obvious errors, but chkdsk is better suited for this task. Refer to the chkdsk documentation for more information on the different options it has.
For maximum data security, also run defrag on your partition if you use Windows ® 9x . This further reduces the risk of data loss. This isn't mandatory, but it's highly recommended. Doing so will make the resizing process much faster and easier.
The ultimate insurance against problems is to always back up your data! Of course, you should back up your data on another computer, upload your back-ups onto the web, on a friend's computer, etc. Do not back it up onto the computer on which you want to install Linux.
 On NT-based operating systems, defragmentation has little to no effect, provided the disk is formatted with NTFS.