Like a car, your computer needs routine maintenance. I highly recommend performing the following 3 steps on a quarterly basis. Not only will this increase the longevity of your computer but will also make your computer healthier and faster.
1. Ccleaner - Clean up temporary and unecessary files.
2. Quick startup - Clean out unwanted applications that automatically start when you startup your computer.
3. Auslogics Disk Defrag - Reorganize and optimize your hard drive. If you are too lazy to install this program, you can use the Windows default Disk Defragmenter. Start-->Programs-->Accessories-->System Tools
You can also find these programs in the Free Downloads section on my site located on the right hand side.