I go back to my original sample with a little tweak...

Code:

$i = 0
Do $KeyName = EnumKey("HKEY_CURRENT_USER\Software\",$i)
   If Not @ERROR
      "Name found: $KeyName" ?
      $i=$i+1
   EndIf
Until @ERROR

...or, if you'd rather...
Code:

$i = 0
Do $KeyName = EnumKey("HKEY_CURRENT_USER\Software\",$i)
   If $KeyName
      "Name found: $KeyName" ?
      $i=$i+1
   EndIf
Until Not $KeyName