You can use Parental Controls to help manage how your children use the computer, for example setting time limits on the hours they can use the computer, the types of games they can play and what programs they are allowed to use
Each person that you wish to enable parental controls for has to have their own user account on the computer, and this can be configured at the same time as enabling the parental controls if you don't already have separate user accounts for each user of the computer
Parental Controls can be accessed from the Control Panel under the User Accounts and Family Safety section
Choose the user you wish to enable controls for, or click Create a new user account to configure a new user
You can then enable the settings and choose the required options for Time Limits, Games and Allowed/Blocked programs
More functionality can be added to the Parental Controls by installing a third party add-on such as Windows Live Family Safety provided with Windows Live Essentials, you can then also control access to specific websites and create a log of all activity performed by a specific user on the computer