Error messages while starting scripts

If the error message

The file "<Scriptname>" cannot be loaded. The execution of scripts is disabled on this system. Please see "get-help about_signing" for more details.

comes up while starting the PowerShell or a PowerShell script the so called execution policy is configured too strict.

In its default configuration,  PowerShell executes only interactive commands, execution of scripts is denied. This security feature makes it more difficult to run scripts of dubious nature accidentally.

To run scripts, PowerShell has to be configured less restrictive. The recommended execution policy is "RemoteSigned". As a result, PowerShell runs local scripts, but denies the execution of unsigned remote scripts. Signed remote scripts are executed if the issuer of the signature is rated as trustworthy and the signature itself is valid.  

To change this configuration, open a PowerShell console and execute the following command:

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned

Hint: You have to execute the command in an administrative console if you use Windows Vista or above with User Account Control activated.