Unless you remapped your key, it should be "F" on the keyboard.
Q: VSXu is not reacting to sound!
VSXu uses a feature in Windows called "WASAPI". Some software does not play well with this.
If you have any audio augmenting software from your computer manufacturer or other tools that meddle
with the sound we recommend that you uninstall them and try again.
Unfortunately some bluetooth hardware has also been known to cause problems. In this case you can try
to play back from a different device.
Q: How do I get rid of the nag text in the corner?
It's there until you purchase at least one DLC pack.