Just to let y'all know the problem was Mixcraft. It's a piece of shit for recording. I'm now using Sonar.
I have not used Mixcraft but you said Audacity was equally guilty and I have used that quite a bit without issues. It is more likley IMHO that the install of Sonar has done some re-configuration.
BTW..ALWAYS worth re installing AI drivers, even the same ones (download fresh). I only ever had one glitch with a 2496 in 3 years and doing that fixed it.
Dave.