If you just use your PC regularly, and have never done any maintenance, you will most likely run into many problems, computer slows down, you get a lot of freezes, files and programs take forever to open.  Windows comes with a set of utilities to aid in the maintenance of your computer.

Disk Defragment : Right click on your C:\ Drive and select the properties option this will bring up a new box, ' Properties ' this box has Tabs with different options. Select ' Tools ' you will see three ' Tools ' in here, It's best to Defragment when you aren't using your computer, as this just upsets the process and you will find it keeps restarting and it will take forever, your hard drive also needs to have 15% free space for the process to work.You should see at least some performance gain maybe even a significant gain.

Disk Clean Up : It's important to keep as much free disk space as possible, a full HDD will run slow, and it will take longer to do the above processes as there are more files to scan.  Virtual Memory requires large amounts of HDD space, if your HDD is full, the space is not available for Virtual Memory.

Scan Disk : Your Hard Disk Drive (HDD) is used a lot during your computer sessions, a lot of use can result in physical damage to the HDD, as well as other damage such as file fragments becoming lost, unknown or unreadable.  Do a thorough scan disk at least once a month.  Before doing a scan disk, close all programs.