Lock Your Workstation
There is probably no easier way to gain unauthorized access to a computer than by walking up to an unattended and unlocked workstation, pointing, and clicking; you are in. When you leave your workstation unlocked, anyone can use it and assume your network identity, gaining access to any applications or files to which you have access. As every person is responsible for keeping his or her workstation secure, you should lock your workstation whenever you leave it, even if you will only be gone for a few minutes. Your workstation screensaver should also have its password protection configured to begin after a short period of inactivity (10 minutes at most is recommended). It is very easy to get sidetracked and stay away from your desk longer than you anticipate, so it is best just to secure your workstation whenever you leave it.
How to Set Up a Screen Saver with Password Protection