Hardware auditing software – any ideas ?

Hi All,

Have been looking for a software package that could do the following:-

1.scan and audit server/Pc hardware across Lan/Wan with no install/footprint on PC/Server.
2.Give detailed results ie network card name and results.
3.Retrieve hardware serial numbers (is this possible ? )if so it may need to target registry entries.

and cost needs to be low (now I am dreaming)

Any ideas ? I have been trawling and download various apps but nothing stands out !.

Thanks