NoahB88:
A few questions that might help point to where the buzz is coming from:
1. How loud is this buzz compared to the audio? If you're recording at too low a gain then boosting the recorded audio a lot to get it loud enough, that may be some of the problem.
2. Do you get the buzz when using Windows Media Player, iTunes etc. to play back audio?
If so, that points to something in the playback/audio out chain being the likely culprit.
3. Is the buzz the same whether you use the USB mic or the laptop's built-in sound, or does it change?
4. If you start a new Sonar project with just one audio track, with it's input set to either the USB mic or laptop mic then, in a very quiet place, arm the track's record button (no need to record, what you're looking for is the background noise floor) what does the track's meter show? If you record as close to "silence" as you can get, what do you get on the track?
In general, laptop/motherboard built-in sound chips aren't the best thing around. They can be OK for playback, but tend to be (electronically) noisy if used to record - sometimes very noisy. They're simply not intended for quality-critical audio work.
ps - if you're using any compressors/limiters, try switching them off and see if that improves things.