You probably didn't notice/don't care, but Gears of War was released on PC today. And like all good PC games, it's launched with a problem. Namely, when you pop it in, Games for Windows Live updates itself, only to hit a snag and be unable to complete the update. There's two ways to get around this. One is :
The easiest is to simply shut down the game after the update is downloaded (you'll know it's safe because you'll be back at the main menu, and not on the "Don't shut down your PC while the update is being downloaded" screen). As soon as you close the game, the update will install automatically and you're good to go.
The other is a little more complicated, so if you can't manage the one above hit the link for more details.
Gears of War and the Games for Windows — LIVE Update [Gamerscore]