Recommended by Nvidia....for what?
Do you have a Nas device with 5 ultra fast drives in raid on the network with gigabit or dual nics?
Are you pulling down from an oc3?
Are you doing heavy client / server work on a similar unit on the other end of the network?
If you answered no to any of these, then the 2nd nic serves no purpose.
In short 2 nics serve 3 purposes (there are more but I'll keep it simple)
1. Load balancing (what you have setup)
2. Failover (one fails, another picks up)
3. Nic 1 Internal IP address (private network) Nic 2 Outside address (ie: web server) (although I don't recommend this - a dmz should be a true dmz)
I'm gonna bet you are doing none of these either?
Ok that said - when are you going to follow my instructions and REMOVE your sound card completely, including the drivers and software and LEAVE THEM OUT, reboot the machine one more time - then load AH2?
If AH2 demands you have a soundcard talk to skuzzy about getting around this but I dont think it's an issue.
You MUST remove some hay from the haystack before you can find that needle. Disable one nic, remove the sound card and try all of this.
You may have IRQ conflicts, or - probably just toejamty sound card drivers. (my bet)
REPEAT - DO NOT remove it, readd it, THEN launch the game. REMOVE THE SOUND CARD and do NOT put it back in. Have a friend take it from you to keep you from trying to troubleshoot this game with a poorly designed sound card. MAKE SURE YOU DONT HAVE ANYTHING EXTRA attached to the computer. Remove ALL usb devices that you can live without for the time being. Just pull them out. Got anything else you can rip out of your computer that you don't need to use? Rip it out! Narrow the problems!
If you still have problems after this:
1. Run a memory checker / system stress tester. Google for these. Memtest86 and I think...ortho? are the names. Be sure to have a smoke detector charged - probably no worries but just a little disclaimer

If your computer shuts down or crashes - then you probably have PS, MB, CPU, or MEM problems. Run memtest86 again. If not this, then you could try another PS first. But it's up in the air what to try next. I personally would rip the fan off my cpu and put some artic silver 5 down, blow out some dust and possibly swap some power cables.
2. If you pass all of these, make sure you don't have anything else plugged into the wall outlet other than what's needed to run your computer...then backup all your data....then, reinstall windows.

Honestly, please - let the sound card, disable the one nic in the bios or at least in device manager, any extra stuff and resintall windows. Then update your windows, update your grafx drivers, then download and run ah2. I'd be very surprised if it fails at that point. If it does, I'm calling bad motherboard. But my guess is IRQ conflicts / crappy sound card. If you narrow it down to a sound card you could always try moving the slots it's in inside the computer. You could try this first but it may be moot as your crappy soundcard drivers will have phantom hooks. I personally would reinstall windows if I were you with almost everything removed. Run bare bones and move up from there until you find the problem again.