Go to Control Panel>Administrative Tools Local Security Policy.
Click help and type software restriction policies on the Search tab.
This information comes from that file:
"To change the default level of software restriction policies
Open Local Security Settings.
In the console tree, click Software Restriction Policies.
Security Settings
Software Restriction Policies
In the details pane, double-click Security Levels.
Right-click the level you would like to set as the defaultand click Set as default.
Notes
To open Local Security Policy, click Start, click Control Panel, click Performance and Maintenance, click Administrative Tools, and then double-click Local Security Policy.
In the details pane, the current default level is indicated by a black circle with a check mark in it. If you right-click the current default level, Set as default does not appear in the menu.
Changing the default level will affect all files on the computers that have software restriction policies applied to them.
Upon installation, the default security level of software restriction policies on all files on your system is set to Unrestricted.
If the default level is set to Unrestricted, you can identify and create rules forthe set of programs you would like to prohibit from running.
If the default level is set to Disallowed, you can identify and create rule exceptions for the programs you trust to run."