#Get all the virtual machines from hyperV
#And store them into an object
$virt_mach = Get-VM
#Try with one specific VM
#..You need to start it before
Start-VM -VM $virt_mach[0]
#To Access to a specific Vm with credentials
#You need ti define credentials like this (or with the get-credentials cmdlet)
$user = "DOMAINmyuser1"
$password = ConvertTo-SecureString "SuperPasswordSoHaRdToFIND" -AsPlainText -Force
$creds = New-Object System.Management.Automation.PSCredential ($user,$password)
#connect to the first VM of the list
Enter-PSSession -VMName $virt_mach[0].Name -Credential $creds
#and then write commandy you need to into the virtual machine
#in here..