If it will open in Audacity, here is what I would try:
Make a safety copy of your original in case you ruin your original by fiddling.
The good thing about Audacity is that you can always undo any tentative change you have made. Just chose undo from the edit menu.
The effects that might work in your case are the equalizer, noise reduction, or high and low pass filters. I'd try equalizing first.
Open the file in Audacity. Go to the effects section and choose the equalizer. Adjust and experiment as needed by ear, then export the equalized file back to your hard drive.
If the video then sounds fine to you, you are done.
If not, reopen the original unaltered file again and use the "noise reduction" effect, with default settings for the first attempt. This effect works very well, but is useful mostly for reducing overall hiss---not ticks and pops at isolated points.
For noise reduction to work properly, you need to use your mouse to highlight a section of the audio that includes ONLY the unwanted noise--not people speaking, background music etc. This is often at the absolute beginning or absolute end.
That portion can be very small--even a half second can work OK. If you don't have such a segment, you can try picking the quietest portion you can see within the waveform.
After highlighting that portion, go to effects/noise reduction and poke "get noise profile". Wait a second or two. Then go to the edit menu and choose select all.
Then go back to effects/noise reduction and choose OK.
You should see the noise reduction effect being applied to the waveform within a few seconds, depending on how long the file is. The effect tries to subtract just the noise profile from the overall sound.
If it still has noise, your only choice is to undo noise reduction from the edit menu and then redo noise reduction--but this time you would set the noise removal DB slider higher than it was on the first attempt. I think the default is 12 DB, so if the file is still noisy, you might try 18.
Play it back, listening carefully for unwanted artifacts. If you set the noise removal DB slider too high, you will hear some newly created and unwanted distortion. So give the file a good listen.
Your last choice would be the high and low pass filter effect. A low pass filter filters out everything above a selected frequency--the treble is cut out. A high pass filter filters out everything below a selected frequency--the bass is cut out.
