Here is a sample powershell script which helps you to check for a registry existance in remote machine. By exploring [Microsoft.Win32.RegistryKey] API you can do much more with registry administration in powershell.
$host = “RemoteComputer”
$Hive = [Microsoft.Win32.RegistryHive]”LocalMachine”;
$regKey = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey($Hive,$host);
$ref = $regKey.OpenSubKey(“SOFTWAREMicrosoftwindowsCurrentVersionUninstall”);
if (!$ref) {$false}
else {$true}
Happy Learning..,
Sitaram Pamarthi