This is the way I recommend players to install or re-install the game and its add ons. Why the instructions? There are a few simple problems that can arise that will cause annoying things to happen when your done installing.

• If this is the first installation on this computer go on to the next step.
  When installing any program into windows, its best for older copies not to be on the hard disk. If you are reinstalling the game then you need to first uninstall TA, this can be done ruthlessly or cautiously. If you wish to save any of the files you have added to the game, maps, units, or AIs, then you must first copy the entire folder to a temporary location. You can now go to the control panel and use Add-Remove-Programs to uninstall total annihilation. After the uninstall is ran, you must then delete the formerly working game folders, usually c:\cavedog\totala, but don't delete your temporary back up. You should now be situated were windows does not know TA was ever installed.

• First install the game right from the main CD. This will install the original 1.x version of TA.

• Once the CD is done installing download and install the 3.1c patch (TA1x-31c.exe) . This will update the installation of the game to version 3.1c. This is a large 8MB file, so do NOT delete it after you install the patch, instead create a save for later folder on your hard drive and put it in there, you WILL have to install the game again someday.
  Because Bone-Yards no longer exists the exe patch with BY in it should not be installed. Also, do not download this patch from any sites you do not trust, there have been some trojans and virus released lately in the TA community.
  If you are getting "can not patch incompatible version" when the patch is run, scan your HD with a virus scanner immediately!

• Now that you have the game installed and updated, its time to install the official addons released by cavedog, if you have them. To do this, it is better to just copy their data files then install them. When installing the addons they just install an obsolete version of 3.0a or 3.0b, this will add unnecessary files to the game folder and waste space and load time. To install them more efficiently, copy these files from the addon CDs to the TA folder;
  Core Contingency: CCMaps.ccx CCMiss.ccx CCData.ccx (CC-Units.ccx and CC-Features.ccx can be used instead of CCData.ccx)
  Battle Tactics: BTMaps.ccx BTMiss.ccx (BTData.ccx is not required)

• There are also 6 units that cavedog released that are not in any of the addons or the 3.1c patch. These units are available officially from the cavedog FTP. Just download each of these cavedog files to a temporary folder and double click them to install.
  Fark , Necro , Scarab , Hedgehog , Immolator , Flea .
  You may also wish to increase the TA Unit limit to 500 instead of 255 with the 500 Patch or 5000 Patch file.

• You are done installing an official copy of Total Annihilation, play it once to test that it works. Now is the time to decide if you want to go further then official files, and use any 3rd party maps, units, AIs, or other addons. If you decide to use 3rd party addons, it is highly recommend you back up the TA folder now, before installing 3rd party files, which are known to be rather risky.

Or to keep it simple, install the game fresh, install the patch, copy the ccx files from the addons, and install the 6 newest units.