It seems for gamers who've bought Gears of War for the PC, it's effectively been a rental until January 28, 2009. Booting up as of Wednesday evidently prompts a message concerning the games' digital certificates supplied by the game's online cheat detection system: "You cannot run the game with modified executable code. Please reinstall the game." Reportedly, Lord of the Rings Online and a few other titles are having similar troubles as well.

Thankfully, Epic (makers of Gears of War) pays attentions to its customers, and some posts in the forums concerning the issue grabbed their attention. User "joeGraf", programmer with the studio, responded yesterday:

"We have been notified of the issue and are working with Microsoft to get it resolved. Sorry for any problems related to this. I'll post more once we have a resolution.

[...] this was a surprise to us too. We aren't casting blame or chewing anyone out. We're trying to figure out how and why it happened so we can get it fixed."

Today he states: "A [Title Update] is in the works. We are doing what we can as fast as [we] can. Again I apologize that anyone experienced this."

Epic's Vice President Mark Rein more recently responded in an e-mail to a customer, explaining the cause and saying: "We made an embarassing mistake: we signed the executable with a certificate that expired in a way that broke the game," continuing, "We know how much this situation sucks, and we apologize for the inconvenience." In a personal e-mail exchange, he mentioned it should be done within a few days (from February 1st).

In the meantime, you can simply set your computer's calendar back a ways -- a step-by-step guide can be found on the Epic forums here.