Since playback volume is low from two different media players...VLC and WMP...that is a possibility, but I doubt it. That would mean that both speakers are damaged and that's nearly impossible.
You said upthread that the volume from a YT vid was ok. If that's the case, I'm thinking your audio drivers may be corrupt or the audio chip may be jacked. I think the next thing to do is to check and see if the audio drivers are ok or need re-installing.
Right click on "My Computer" and left click on Properties.
On the left side of the window, click on "Device Manager"
Click on the tiny arrow next to "Sound, Video, and Game Controllers"
You should see at least one audio device listed..."blah blah Audio"...probably two audio devices listed if not more.
Right click on each and select Properties. In the General tab under Device Status, you should see "This device is working properly". If not, click on the Driver tab and select "Update Driver" button and follow instructions. Windows will go out on the web and find the latest driver and install it.
Repeat the above with each audio device listed. If you end up installing new drivers, you will need to restart afterward. If all audio devices show to be working properly, just cancel out of each window.
If you see 3 audio devices, one has probably been installed by another app and there may lie your problem as that one is probably set as the default audio device. Let me know if such is the case.
Everything is in pretty plain English. Just don't click on Uninstall.