$UserName = "IPAddressusername"
$Password = ConvertTo-SecureString "password" -AsPlainText -Force
$psCred = New-Object System.Management.Automation.PSCredential($UserName, $Password)
$s = New-PSSession -ComputerName IPAddress -Credential $psCred

$sysprep = 'C:WindowsSystem32SysprepSysprep.exe'
$arg = '/generalize /oobe /shutdown /quiet'
$sysprep += " $arg"

Invoke-Command -Session $s -ScriptBlock {$sysprep}

$sysprep = 'C:WindowsSystem32SysprepSysprep.exe'
$arg = '/generalize /oobe /shutdown /quiet'
Invoke-Command -Session $s -ScriptBlock {param($sysprep,$arg) Start-Process -FilePath $sysprep -ArgumentList $arg} -ArgumentList $sysprep,$arg