Theater View in MC12 is driven by Direct3D, so depends on your graphics hardware a lot more than it used to. You should be running the latest version of DirectX available for your OS, which (unless you have Vista) should be DirectX 9.0c.
If you do Start --> Run and type dxdiag.exe and hit enter, you should get the DirectX diagnostic. It'll tell you what DirectX version you have. If it isn't 9.0c, then go here and download it from Microsoft:
http://www.microsoft.com/windows/directx/default.mspxIf so, then you can try doing the DirectDraw and Direct3D acceleration tests on the Display(s) tabs of the DirectX Diag dialog as well. If these fail, you might need to try reinstalling DirectX (download it from Microsoft and reinstall) or try reinstalling your graphics drivers.
I don't know much about the g550, but a brief look around the net showed that the chip was released in June 2001, around the time of the GeForce 2 nVidia cards. It also appears in some of the brief reviews I've skimmed that it didn't support any hardware T&L features (now called Vertex and Pixel Shaders in DirectX parlance) so it was not even considered "acceptable" at that time for 3D uses. With that, it might be time to consider investing in a new video card. Any
current low-endish ATI or nVidia video card would be able to easily handle the requirements of Theater View. I'd look at the ATI X1300 line and the nVidia 7300 line, which are generally available for PCI, AGP, or PCIe.