With v9 you've got 4 audio tracks to work with, how many are you using?

If you have a free track, you could copy the audio from the track you've been working on to a new one. A system restore as you say

"like searching for an audio fountain of gold"

I think you would find that WaveHammer is pretty close to an 'audio fountain of gold' in it's ease and simplicity of use, combined with the generally overall good results. It really is just a few clicks solution and solves many volume ills.

It's not a miracle, and if you have some audio that is very quiet along with the loud stuff you'll probably still want to normalize those first, but this is a very minor issue that you've already learned how to do. You would be well rewarded to spend a few minutes learning how to use it.

Late to the thread as usual, but I wonder besides all the helpful comments if I really understand what OP is having difficulty with.
Can you state where the video comes from...e.g a recorded play or scene with audio which you've recorded using the camcorder's microphone, which plays back ( on the camera) OK . . . . .within the severe limits of the built-In speaker ( 0r better still plug-in headphones ).
Most of our recorded audio varies from quite loud to rather too quiet - because of our inability to control the recording process.

Are your videos just like ours? + OR is there some other effect we should know.

I use the "Volume" effect on Audio tracks - and that's often "after" I've been through a rough-cut using Sound Forge Studio (( Came with the "Suite" ).

When setting the playback average levels you need to adjust the master-slider so the average is about minus 12dB - this gives you plenty of "headroom" for loud passages and bangs, cracks etc - since you cannot allow the waveform to reach 0dB .
SMS helps us by making the near-zero ( dB) region turn Red . . .

By having your movies set to a similar level then there is no need to keep adjusting the playback Volume on an amplifier+ speaker set-up. For this reason I have a "Jingle" playing as the credits open---- so the audio can be set correctly.

Yes it is rather techy - but then so is life in general and as you find fixes your movie-making becomes easier.
I've suggested SMS includes a prre-recorded Clips which beginners and Others can use as a "Standard" for learning "How-to..." since a beginner may have faulty files in the sense their technique/Settings are not correct . . . at least you'd expect the SMS Clips will be deliberately set. Of course there's the issue of 50/60fps Standards, but these files will only be a few Mb and could be downloaded from this SIte. . . . giving Sony an opportunity to demo how their new software can make things even more interesting . . . were They listening? - You know that!

Does that help?
Do let us know where the problem originates, etc.

I read this rather painful series of messages a couple of years later (Jan 2018) as it popped up when I was trying to sort a problem with normalization. Most people on this thread tried really hard to give some good advice but it did not seem to connect with Dave - that happens sometimes.

Howwever, I wanted to say a special thank you to "Jillian" who included the following sentence in her contribution: " Please note that if you have one peak much higher then the rest of the clip (such as a cough or loud noise) that will become the high point and the remainder of the clip will still be much lower."

That exactly solved the problem I was having - one part of my sound track apparently refusing to respond to the normalize command. I looked closely and there was a peak as someone dropped a pen off their desk. I cut the clip just before and after the sound (without deleting it) and the sections just before and after normalized perfectly.

Just exactly solved my problem - if not Dave's! Thank you.

Peter, the niftier way is called rms normalization in sound forge. You set an optimized loudness level, which is a lot different than either peak level or volume, and then set a peak limiter in the same dialog to cap the loud noises to legal limits, between -1 and -6 dbfs.

Use -12 rms as a starting point for music, and -6 for speech. Aurally compare your loudness to iTunes, as that is the traditional de facto loudness standard for the internet.

If you see flat top peaks when you zoom in on the timeline, there is really not much you can do in Vegas or soundforge to prevent distortion. It pretty much is what it is. Feel free to start your own thread topic with good questions like this next time around.

Thank you Musicvid - looks like I should try to get to grips with Sound Forge. Video editing is a steep learning curve and after three years off and on use I feel pretty much at home with Movie Studio in a way I never did with Premiere. At the risk of channelling Dave, the thought of getting to grips with new layers of complexity is daunting (e.g "optimized loudness level, which is a lot different than either peak level or volume" is like hearing to a language you cannot quite speak). The problem is that I use this software when I am on a mission with sharp deadlines etc. so I learn what I cannot do without, swap lessons with colleagues on line but rarely swim into deeper waters and learn what would make my life easier. I will try to diary up some time to explore Sound Forge and give it a go.