The PMDG B744 add-on for is considerably better than the Aerowinx product, and costs a lot less! Though, of course, you need MSFS2004 and a fairly meaty computer to run it. Don't be fooled by the 'game' tag; this is a full-blown simulation of the real thing, with appropriate differences for diferent airlines' versions of the aircraft. The aircraft systems are modelled in great depth, and all EICAS warnings and procedures are included. As ColeTrickle says, download the manual and have a look for yourself.
I have a few thousand hours on the B747 (200, not 400), and I can vouch for its authenticity.
Scroggs