How to backup virtual machines using powershell

from http://prosjekt.mindre.net/post/Powershell-script-for-snapshot-and-exporting%28backup%29-Virtual-Machines.aspx download the CreateVmBackups.ps1 Powershell script. Set Powershell scripts execution policy to RemoteSigned and create a scheduled task for this script. To run a Powershell script in Task Scheduler enter Powershell as program and "& 'C:\Hyper-V\CreateVmSnapshots.ps1'" as argument.