In PowerShell you easley can test a registry key with the cmdlet Get-ItemProperty.

PS C:\> $key = $(Get-ItemProperty “HKLM:\SOFTWARE\LJS”).LarsJostein -eq “Silihagen”
PS C:\> $key
True

PowerShell example where  you test the installed Operations Manager Console version:
function OpsMgrVer
{
return $ver = $(Get-ItemProperty “HKLM:\SOFTWARE\Microsoft\Microsoft Operations Manager\3.0\Setup”).CurrentVersion
}
function TestVersion
{
$nr = OpsMgrVer
if (OpsMgrVer -ge “6.0.6270.0″)
{ Write-Host “SCOM 2007 SP1 is installed. ServerVersion: $nr” } else { Write-Host “SCOM 2007 SP1 is not installed. ServerVersion: $nr” }
}