Johnobrucy

Just to get things out of the way, here's all the computer specs:
Asus A8N-SLI Deluxe Motherboard
AMD Athlon 64 3700+ FSB: 200MHz Multiplier: 11x
BFG GeForce 6800 GT OC w/ 91.31 Forceware Drivers Not Overclocked (beyond factory defaults)
1GB PC3200 DDR Crucial Ballistix RAM
Antec TP-II 550W PSU

Now for the problem:
I recently installed Madden NFL 06 and went to play it, configured all the options to what I thought my computer was capable of for when the game came out and etc.. only to find that, in-game, there are large artifacts that flash around. They're usually black or white strips that look almost like they're raining down. They make playing pretty difficult even though most of the rest of the game is intact. They don't appear on any menus and only when actually playing. I've looked everywhere for how to fix them but can't find anything.

I've updated the game to its newest patch as well. I also have tried to play the game without the patch and have done both w/ and w/o patch playing with the 84.21 Forceware drivers. I've also tried using VSync on and off as well as reducing resolution and detail settings both through the game and through the nVidia control panel. Additionally, I don't have any kinds of problems in any of the other games I play (HL2, F.E.A.R., MVP Baseball '05, Tiger Woods PGA Tour '06).

I'm pulling my hair out and really would like to play this online with my friends, any suggestions on how it could be fixed?