See if this works for you:
Select Top 1000000 tblAssets.AssetID,
tblAssets.AssetName,
tblAssets.FQDN,
tblAssetCustom.Manufacturer,
tblAssetCustom.Model,
tblAssetCustom.Serialnumber,
tblBIOS.SMBIOSBIOSVersion,
tblBIOS.ReleaseDate
From tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Inner Join tsysAssetTypes On tsysAssetTypes.AssetType = tblAssets.Assettype
Inner Join tblBIOS On tblAssets.AssetID = tblBIOS.AssetID
Where tblAssetCustom.State = 1