Safedisc 2.51 protected CDs

[fin2head]

I am having trouble with playing MOHAA, Sudden Strike and SS Forever and other game titles apparently protected by Safedisc 2.51.xx protection. A little background prior to troubles. My OS is Win98 SE, these titles are all originals and were playable before attemping to CD copy thegame Total War: Medival. Of course the backup failed. I attempted to unlock with Deamon tools and others with no luck. Then after a little research discover can not unlock needs a different technique. Now the big trouble is I no longer able to play or reinstall the games and have them start. The only thing that happens is the splash screen shows briefly then back to desktop. Please help or explain what is happening.
I have tried tools from your website and others on these games with no luck. I would like to make backups but need get original games working again. Hope I do not have to reinstall OS. Also tried using safedisc2cleaner ,the program could not find TEA key. What is TEA key?