Dropout

Ok. I am getting dropout like crazy. I've gone through the whole troubleshooting list, turned off hardware acceleraters, shut down background programs, lowered sampling rates, you name it, I think I've done it. Changed vidoe cards....the thing is, is that I've used this sound card in an older, slower machine, and it worked great. Its an M-Audio Delta 1010Lt. Maybe thats the problem. Is it possible this sound card has compatibility issues with this system? It plays other media fine...media player, whatever...it just will not run in Sonar. Any help, please?