i can't help you with your main problem, maybe try to reinstall drivers
but can advice you how to get rid of the second cg miner
use config file to setup each gpu's individually, just let your cg miner write it for you
and then change values as you want
should be like:
...
"intensity" : "13, 17",
"gpu-engine" : "900-1000, 900-1100",
"gpu-thread" : "2, 1",
...