No. 1 software maker Microsoft has taken a minority stake in online-only game developer VR-1, according to the gaming company. Microsoft converted royalty advances into a minority equity investment, VR-1 said. VR-1 developed the first two "pay-for-play" games on Microsoft's MSN Gaming Zone. The two companies have agreed to a large distribution deal for Fighter Ace, MSN's World War II air combat game, which was developed by VR-1 and launched in December 1997.