How can you run 3 conquer online accounts at the same time

The simplest way is to have more than one computer running it. However the much more practical method for doing this would be to hack/modify the game with what is called multi-client. You can either do it yourself with some hex editing tools you can find online or you can get a pre-made multi-client which only requires you to replace the conquer app in the conquer folder with the modded one. Elitepvpers.de has both a walkthrough for making one for yourself and an updated pre-made one on their forums.