A Japanese-language version of a Sega Dreamcast role-playing game has become infected with a computer virus.

The game, Atelier Marie, includes a screensaver which is infected with the highly damaging Kriz virus.

Although the Dreamcast itself is left unscathed by this, anyone loading the screensaver onto their PC from the game's CD-ROM will be in for an unpleasant surprise, when the virus activates on Christmas Day.

Kriz will erase the CMOS setup and attempt to corrupt a computer's BIOS chip in a similar way to the CIH (aka Chernobyl) virus. This effectively paralyses the entire computer, and forces a user to replace the BIOS chip.

The virus also attempts to overwrite all files on local hard disks and network drives with garbage, as explained in more detail here.

Natasha Staley, technology consultant at anti-virus firm Sophos, said the virus probably ended up on the CD-ROM because one of the game's developers was working on an infected machine. Kriz is over a year old which suggests "quality assurance wasn't up to much", she added.

Kool Kizz, the Japanese developers of Atelier Marie, have recalled the game from shop shelves and posted an apology to affected users.

Although the infected version of the game is only likely to have been widely distributed in Japan, anyone who has a copy of the game is advised to either return or destroy it. ®