If there is a need to pass specific credentials to Get-WmiObject in order to gather information from remote machine, here is how you can do it:

$LAdmin = "DOMAIN\Administrator"
$LPassword = ConvertTo-SecureString "Password!" -AsPlainText -Force
$Credentials = New-Object -Typename System.Management.Automation.PSCredential -ArgumentList $LAdmin, $LPassword

Once $Credentials object is created you can easily use it to gather information from remote PC:

Get-WmiObject -ComputerName $computername -Class Win32_VideoController -Namespace "root\cimv2" -Credential $Credentials