Defragmenting is the process of reading all the bits on the file system and re-arranging them to be contiguous. This is a pretty time intensive process and is quite complex for an operating system to handle. Imagine, you’re trying to access a file that you know resides on particular place and the next time you go to access the same file, the file’s position has changed, since the user ran a defragmenting utility over the file system. For this reason, the default defrag utility which comes bundled with windows (defrag.exe) does not even attempt to defrag any of the important system files that windows uses. So, even after a long and lengthy defragmenting session, there is a good chance that your computer is still not running as well as it can. To get over this problem, the kind souls maintaining the sysinternals tools over at Microsoft Technet have released a nifty little utility called PageDefrag. Using PageDefrag to defrag system files on Windows is pretty simple. Just extract the pagedfrg.exe application from the zip file that you downloaded from the above link and execute it. This is what you will see. Select the “Defragment at next boot” option, press “OK” and reboot windows. When Windows starts to load, PageDefrag will automatically run and do its job, which is defragmenting the system files, and then complete loading windows after its done. How PageDefrag gets over Windows inability to defrag system files is that it sets itself to run even before Windows has started and so accesses those files before Windows gets to claim any control over them. Isn’t that cool ? In my case, none of the system files needed defragmentation and so the process was over in just under 5 seconds but if you have not reinstalled Windows in some time, defragmentation can take a long time. Factor in at least 15-20 minutes for the job.