$username = get-content "C:\Temp\username.txt"
$password = get-content "C:\Temp\password.txt"
$password = convertto-securestring $password -asplaintext -force

Write-Host "Importing credentials"
$creds = New-Object System.Management.Automation.PSCredential($username,$password)

Write-Host "Joining computer to domain"
add-computer -domainname "contoso.com" -cred $creds -oupath "OU=Computers,DC=contoso,dc=com"

#Check activation once more
Write-Host "Checking activation"
slmgr /ato

Write-Host "Resetting execution policy"
Set-ExecutionPolicy -ExecutionPolicy Restricted

Write-Host "Cleaning up copied files"
Remove-Item -LiteralPath "C:\Temp\join.ps1" -Force
Remove-Item -LiteralPath "C:\Temp\username.txt" -Force
Remove-Item -LiteralPath "C:\Temp\password.txt" -Force

Write-Host "Restarting in 15 seconds"
Start-Sleep -seconds 15
restart-computer