Based on what you’ve already tried, I’d suspect that the laptop card is bad. Is this the generic Dell soundcard or something else?
If you plug the mic directly into the M-Audio box, do you hear anything from the headphone jack? Be advised that I use the M-Audio Firewire 410 at work and have found that it’s output is not as high as I’d like.
As Gary said, did you check the battery? I know you said it’s brand new but that’s not saying the battery is 🙁