powershell search multiple domains for computer - powershell

Question

I need some help. I wrote a PowerShell script that grabs a text file as an input with a list of computer names. It then checks the Active Directory for the machine name. If the machine is found it writes it to one text file, and if the machine is not found, it writes it to a separate file. The idea being I get two lists... A "good" and a "bad" list. the problem is that it only queries the domain I am in and I need it to query all the domains in a forest and am stuck. can someone lend a hand? Here is my code as it stands:
Import-Module ActiveDirectory
$AdminCredentials = Get-Credential "Domain\AdminAccount"
$objForest = [System.DirectoryServices.ActiveDirectory.Forest]::GetCurrentForest()
$domains = #($objForest.Domains | Select-Object Name)
$computers = gc -Path "C:\MachinesInDifferentAds.txt"
$computer_count = $Computers.Length;
$i = 0;
foreach ($computer in $computers) {
Try
{
(Get-ADComputer $computer -Credential $AdminCredentials | FT Name)
$computer | out-file -append -filepath "C:\ComputersInAd.txt"
}
Catch
{
$computer | out-file -append -filepath "C:\ComputersNotInAd.txt"
}
$computer_progress = [int][Math]::Ceiling((($i / $computer_count) * 100))
Write-Progress "Querying the AD" -PercentComplete $computer_progress -Status "Percent Complete - $computer_progress%" -Id 1;
Sleep(1);
$i++;
}