Disk defragmentation can cause a computer to run slowly, so it's an essential step to keeping your computer running smoothly. Here's why and how.
Over time, files are put on your hard drive at random and can cause "fragmentation." In other words, the files are located all over your drives, and defragmenting your drive organizes the files and allows Windows to find the most accessed files faster. If you have an SSD drive, you can instead optimize TRIM.
Before we start, we recommend cleaning up your computer, including uninstalling apps you don't use, cleaning your hard drive of junk files, and removing apps from startup. Check out How to Make Your Computer Run Like New in 4 Easy Steps.
How to Defragment Your Hard Drive in All Windows Versions
Open File or Windows Explorer.
Right-click on your hard drive and click Properties.
Click on the Tools tab.
Click on Optimize.
Some people recommend you check the disk for file system errors, but unless you're having a problem, we never bother.