Have you just gotten the game and this is happening? Or have you been playing it for a while and the flickering just started?
Do you have any patches installed? Also, please post your system specs or the Tech folks probably won't be able to help you much. In fact, they require you post them.
Sorry, man... the game won't run any better on your system, I'm afraid. I'm kind of surprised it runs at all. Here's EA's listed system requirements:
1.0 GHz Intel Pentium III or higher
256 MB RAM
1700 MB free hard drive space
32 MB DirectX 9.0c Compatible Video card
16x CD-ROM/DVD-ROM drive using 32-bit CD-ROM driver
Sound card with DirectSound support and DirectX 9.0c compatible driver
Your RAM is severely lacking, that's probably what's causing your flicker. What video card do you have?