XP not detecting SLI

Im running windows xp SP2, 2 evga nvidia 8800GT cards, Asus Maximus motherboard, and i have the newest drivers. But i can not get the sli working, ive looked up how to enable sli and its supposed to be in my Nvidia control panel under Manage 3d setting, but theres nothing there that says anything about sli. I have the cards connected to eachother and its setup in the bios to PEG. "PCI EXPRESS GRAPHICS"

 

I've had problems with enabling SLI also. In my case, I started with one card and added a second card about a month later. I had to remove all the drivers with only one card installed. Reboot. Go into BIOS and switch from single card to SLI mode. Shut down. Install 2nd card. Power up and install the latest drivers. Reboot. Go into the NVidia Control Panel and enable the SLI (if it doesn't auto enable). Reboot.
That's what I had to do. I hope this helps.