Hello Sam,
As I said, cause the problem suddenly occured and you never had the same problem before, I think the problem is caused by your cable.
The volume of wave is indeed a good thing. Normally, wave is founded near the volume. To go into the volume, go to start-allprograms-Bureau-accessoires-Entertainment-Volume control (this is better then trying to look for the logo in the systremtray as not everysystem has that). Then you should see a screen like this:
Don't mind this is in dutch, the position of the controls should be the same. So the first two should be @ the highest level.