Assets Missing Quickfix Data - Last 60 Days

[TimH]

The code below displays assets that haven't received patches (quickfixes) in the last 60 days. However, assets that haven't received any patches are missing. How can I include the logic 'tblQuickFixEngineering.InstalledOn = NULL' to the query below?

Select Top 1000000 tblAssets.AssetID,
  tblAssets.AssetName,
  tsysOS.OSname,
  tblAssets.Username,
  tblAssets.IPAddress,
  tblAssets.Description,
  Max(Convert(date,tblQuickFixEngineering.InstalledOn)) As lastPatchDate,
  tblAssets.Lastseen
From tblQuickFixEngineering
  Join tblAssets On tblAssets.AssetID = tblQuickFixEngineering.AssetID
  Join tsysOS On tblAssets.OScode = tsysOS.OScode
Where tsysOS.OSname Not In ('') And IsDate(tblQuickFixEngineering.InstalledOn) =
  1
Group By tblAssets.AssetID,
  tblAssets.AssetName,
  tsysOS.OSname,
  tblAssets.Username,
  tblAssets.IPAddress,
  tblAssets.Description,
  tblAssets.Lastseen,
  IsDate(tblQuickFixEngineering.InstalledOn)
Having Max(Convert(date,tblQuickFixEngineering.InstalledOn)) < GetDate() - 60
Order By lastPatchDate Desc

[TimH]

I'm also having a hell of a time trying to build a chart off of OSname.

I tried the following but the data is definitely wrong. Suggestions?

Select Top 1000000 tsysOS.OSname,
  Count(tblAssets.AssetID) As Total
From tblQuickFixEngineering
  Join tblAssets On tblAssets.AssetID = tblQuickFixEngineering.AssetID
  Join tsysOS On tblAssets.OScode = tsysOS.OScode
  Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Where tsysOS.OSname Not In ('') And tblAssetCustom.State = 1 And
  IsDate(tblQuickFixEngineering.InstalledOn) = 1
Group By tsysOS.OSname
Having Max(Convert(date,tblQuickFixEngineering.InstalledOn)) < GetDate() - 60
Order By Total Desc