Ugh. Game won't play

[Torvald Von Mansee]

I installed the multiplayer demo for Return To Castle Wolfenstein, and it changed some settings in my computer and now SHIII won't play. I don't even know what settings were changed, as I'm not really that technical a person!!! I think it's something in the display settings (when I start the game, and it switches to the opening sequence w/the logo and then the cutscene of the attack on the convoy, the screen goes "bloop" and everything blacks out for a second or two...it's less smooth than how this worked before the settings got changed).

Any ideas on what to do? I uninstalled RTCW MPD for what it's worth, and did some fiddling w/the settings.

EDIT: I can get to the menu page, but if I try to resume a career, the game quits and offers to send an error report to MS. I'm also running GW for what it's worth.