Command and Conquer, was one of the greatest Strategy Series that was ever created. A while ago the older Games have been released for free.
The official CDs and How to install you can find here.
However it is easier to just install from cncnet.
Fun additional stuff for Red Alert can be downloaded at:
Getting Red Alert to run on Windows 7 with correct colors:
- Go to http://hifi.iki.fi/cnc-ddraw/#download
- Copy the .dll file into the Red Alert Directory
If that is not enough, take a look at