ok if you have gears pc this problem just started recently.

if your game gives you a code about a modified code.

It means the game certificate expired.

In order to play again.

You need to set back your date to 1/5/2007 so you dont have to worry about it happening again for a while.

Then you need to get the update on this recent problem here.

http://forums.epicgames.com/showthread.php?t=656348 it is a temporary fixx.

Xbox live may be up on monday i believe.