1. First open start menu and type msconfig in run dialogue box.
2. It will open a System Configuration Utility box. Click on Start up tab in it. It will tell you about the programs which run on the start up of computer.
3. Stop some unnecessary running processes. Don't stop some processes running in window.
4. It will remove the extra load from RAM and make computer fast.
5. You can also delete temporary files from your computer. Type %temp% in run dialogue box. Select all temporary files and delete them. These files occupy only space in computer. Also delete files by typing temp only.
6. Delete files from 'prefetch' folder in Windows folder in 'C' drive.