Tip - use headphones when you are recording guitar parts. Pan and mix the tracks as you record so you can get a better feel for what works, also helps to get rhythm tracks a lot tighter if you use 100% pans. Drums in the headphones will also reduce the potential for extraneous noise bleeding over to the mic (as you experienced). You may have to move out of the room with the amp to do this though, otherwise it might be too noisy for headphones (an isolation booth is ideal but not many people have those in their bedrooms!).