Something like this?
Select Top 1000000 tblAssets.AssetID,
tblAssets.AssetName,
tblAssets.IPAddress,
tblAssets.Domain,
tblAssets.Lastseen,
tblAssets.Lasttried,
tsysOS.OSname,
tsysOS.Image As icon,
tblAssets.SP,
tsysIPLocations.IPLocation
From tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Inner Join tsysAssetTypes On tsysAssetTypes.AssetType = tblAssets.Assettype
Inner Join tsysOS On tblAssets.OScode = tsysOS.OScode
Left Join tsysIPLocations On tblAssets.IPNumeric >= tsysIPLocations.StartIP
And tblAssets.IPNumeric <= tsysIPLocations.EndIP
Where tblAssetCustom.State = 1