Try this:
Select Top 1000000 tblassets.AssetID,
tblassets.AssetName,
tsysassettypes.AssetTypename,
tsysassettypes.AssetTypeIcon10 As icon,
tblassets.IPAddress,
tblassets.Lastseen,
tblassets.Lasttried,
tblassets.Mac
From tblassets
Inner Join tblassetcustom On tblassets.AssetID = tblassetcustom.AssetID
Inner Join tsysassettypes On tsysassettypes.AssetType = tblassets.Assettype
Where tsysassettypes.AssetType = 25 And tblassetcustom.State = 1