noise reduction

I am running Audacity 2.0.5 in Windows 7 Home Premium. I am a complete newbie and know absolutely nothing whatsoever about what I am doing. I am trying to remove background noises from audio of interviews so that they can be transcribed more easily. In particular, I have one with loud construction going on in the background. I think I was successful in removing a saw buzzing noise by using the defaults. However, when I tried to remove extremely loud sharp bangs, the result was considerably diminished volume throughout the entire recording, which made it impossible to hear the soft-spoken interviewee. My guess is that it might be possible to adjust the defaults and get better results. Is that true or is it a lost cause or would it take far more technical expertise than a 75y old neophyte could manage? Thanks.

You may be able to get slightly better results with careful tweaking and experimenting with the parameters, but basically it is probably a lost cause. The workmen are actors in your show - too late to ask them to stop.