Sony acknowledged the problem last week in a postcard sent to members of its PlayStation Underground fan club, warning members to be careful with holiday demo discs sent out last month. Don't play the trial version of the Capcom adventure game "Viewtiful Joe 2" included on the disc, Sony warned, unless you want to start over from scratch on every PS2 game you own.

"It has just been brought to our attention that there is a glitch in this demo which will erase all of your saved files from your memory card," Sony stated in the advisory. "If you have not yet played the 'Viewtiful Joe 2' demo, please remove your memory card from your PlayStation 2...before you load the Holiday 2004 Demo Disc. Sony Computer Entertainment America would like to express our sincerest apologies for any inconvenience this may have caused you."

Memory cards are used to save progress in games, allowing players to resume a game from where they left off the last time they played. For a complex game such as the new "Grand Theft Auto: San Andreas," which requires an average of 80 hours of playing to complete all missions and side trips, the files saved on the memory card can represent months of diligent work and play.

Game players posting in online forums on Sony's PlayStation 2 site and other Web venues reported exactly such tragedies. "I was five missions away from beating "GTA: San Andreas," wrote one poster at the Sony site. "Now it's all...down the drain."

"Deneteus" wrote in another forum: "I feel that Sony has just wasted part of my life...My play time is valuable. It is a part of my life that I can't get back. I shouldn't have to resort to cheating just to get back to where I was before."

A representative for Sony Computer Entertainment America said: "We recognize this as a serious issue and are doing everything we can to alert the consumers who received the demo. We have sent out postcards and e-mails alerting the recipients of the glitch, as well as posted the information on various message boards to alert consumers before playing this demo."

Copies of the Sony demo disc sent later in November don't include the "Viewtiful Joe 2" demo or the glitch. Capcom representatives have said the glitch is not replicated in the full version of the game.