Need Help with Custom Query all computer that do not contain a specific regkey

[chadsharp]

I have to audit all of our computers for the presence or absence of a specific piece of software.
Getting the machines that have the software is easy by scanning for the registry value but how do I search for machines that do not have that value? Here is what I have so far but it seems to pull all(2100+) computers on the domain?

Select Top 1000000 tblAssets.FQDN,
tsysOS.Image As icon,
tblRegistry.Regkey,
tblRegistry.Value,
tblAssets.AssetID,
tblAssets.AssetUnique,
tblAssets.Domain,
tblRegistry.Lastchanged,
tblAssets.Username,
tblAssets.Userdomain,
tblRegistry.Valuename
From tblAssets
Inner Join tsysOS On tsysOS.OScode = tblAssets.OScode
Inner Join tblRegistry On tblAssets.AssetID = tblRegistry.AssetID
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Where tblRegistry.Regkey != 'HKEY_LOCAL_MACHINE\SOFTWARE\HITACHI SOFT\HIBUN-AE'
And tblAssetCustom.State = 1
Order By tblAssets.AssetUnique

[chadsharp]

Thank you for the response this is just what I needed.

[RCorbeil · Accepted solution]

Try this:

SELECT TOP 1000000
  tblAssets.FQDN,
  tsysOS.Image As icon,
  tblAssets.AssetID,
  tblAssets.AssetUnique,
  tblAssets.Domain,
  tblAssets.Username,
  tblAssets.Userdomain
FROM
  tblAssets
  INNER JOIN tsysOS         ON tsysOS.OScode = tblAssets.OScode
  INNER JOIN tblAssetCustom ON tblAssets.AssetID = tblAssetCustom.AssetID
WHERE
  tblAssetCustom.State = 1
  AND NOT EXISTS ( SELECT tblRegistry.AssetID
                   FROM tblRegistry
                   WHERE tblRegistry.AssetID = tblAssets.AssetID
                     AND tblRegistry.Regkey = 'HKEY_LOCAL_MACHINE\SOFTWARE\HITACHI SOFT\HIBUN-AE'
                 )
ORDER BY
  tblAssets.AssetUnique