Computers become a necessary element on our daily life. After the whole day tiring work, we turn on computer to access different kind of websites in order to relax ourselves. Computer is also largely applied in industry to save labor force. It can quickly transfer data, obtain message, select information for users. However, computers have several disadvantages. It brings some addictive items to children and it needs to be maintained regular for better performance. Besides, privacy is another concern for users, we need more security policies and regulations to protect our personal information.