I don't know too much about older drivers. If I down load a older driver does it take over the computer? Affecting other games or programs?
If you download a driver for your video card, it only affects the video card.
It does not "take over your computer" unless you get an infected driver (maybe not a driver at all) from a questionable website.
It may or may not affect other games in a negative way.
It's unlikely it would affect programs (other than games) unless you were using programs that required 3D graphics acceleration -- maybe game-making programs.
Would the computer know which drivers to use? and when?
The computer uses whatever version of the drivers you've installed.
You can download every driver for your video card that was ever made, but the computer will only use the drivers you've installed.
Often driver packages will prompt you to uninstall the old drivers before installing the new ones.
You can always go back to a previous version of the drivers if the ones you try don't work out for you.
This site has links for how to do this using different versions of Windows.
http://pcsupport.about.com/od/driverssupport/f/roll-back-drivers.htmWhat is a NoCD ? How would that work?
A NoCD bypasses the check for the original disc. Modern disc-based copy "protection" uses checks that go far beyond checking to see if there is a CD in the drive. They force the CD/DVD drive to scan parts of the disc that aren't normally used and use encrypted data, incorporating features like how fast the drive reads the disc. They delay how quickly the game starts and can wear out your drive. NoCD's were once mainly used by people who didn't want to have to put the disc in the drive every time they started the game -- or didn't like the delay the copy "protection" caused when starting the game -- or by people who downloaded illegal copies of the game. Nowadays NoCD's are often used by people who aren't able to play their legitimately purchased games due to copy "protection" that doesn't work properly with their version of Windows or with their CD drive. Sometimes there is no NoCD available for your particular version of the game.
I can't tell for sure that this is a copy "protection" problem, but considering the sneaky "trigger functions" that modern copy "protections" use, I wouldn't be surprised. It's one reason download versions of games may be better -- no CD check that can cause issues.
Do you think I should unistall the game and start over? Would hate to get back to that high level and lose it all again.
Unless you somehow got a corrupt install, you'll probably have the same problem once you replay to where you are now in the game.
Are you able to load old saves? If your old saves are still good, be sure to back them up somewhere if you decide to try re-installing the game.
Do you have a patched version of the game? It's had at least two patches -- 1.16 and 1.17 .