As had been expected, Electronic Arts has released the original Command & Conquer: Red Alert for free to celebrate the release of the original Command & Conquer 13 years ago.At FileShack you can find the ISOs for the Allied and Soviet discs. Both are about 500mb downloads.

Red Alert can be installed under Windows XP, 98, 95 and ME. Vista is not officially supported, though it should be able to run on that OS as well.