Actually, if you want to determine if a value is present, you would use EnumValue. Here's the sample from the manual, modified to exit if the value "XYZZY" is present in the registry key.
 Code:
$Tag = 0
$Index = 0
$ValueName = ENUMVALUE("HKEY_CURRENT_USER\Console\Configuration", $Index)
While Not @ERROR And $Tag = 0
  If $ValueName = "XYZZY"
    $Tag = 1
  EndIf
  $Index = $Index + 1$
  ValueName = ENUMVALUE ("HKEY_CURRENT_USER\Console\Configuration", $Index)
Loop
If $Tag
  "Registry value XYZZY exists!"
EndIf


Glenn
_________________________
Actually I am a Rocket Scientist! \:D