@Alex57 

Since I am not sure if do fully understand the issue, my suggestions may perhaps not hit the point:

In case the video itself is too silent, you may try to use another Video-Player application like VLC (freeware) which allows the Audio to be boosted up to 200%. (use the mousewheel since the volume-slider stops at 125%)

 -windows.html

If you do not want to install any software on your computer, you may use the portable-Version (.ZIP = no installation/no admin-rights needed; just unzip the package and run the software).

Another option may be to "edit" the video to increase the Volume of the Audio-Track in the Videofile:

perhaps with a free tool like "XMedia Recode" which is also available as portable-Version: -recode.de/en/

(such tools are usually not self-explanatory... I may give you some hints, if you want to go that way..)

Xmedia Recode Download Old Version