Sound is gone

This morning, my sound worked fine. But somewhere along the line, I lost it, i.e. I have no sound. I ran the Creative Diagnostics test, but and it says:

 

Hardware Detection                                        Pass

Wave Driver                                                    Fail

MIDI Driver                                                      Fail

Mixer Driver                                                     Fail

DirectSound 3D Driver                                    Fail

Mixer Settings Check                                      Fail

 

When I click "Begin Fix" a box pops up that says:

 

"The Current Problem cannot be fixed automatically. Reinstall the software of your audio hardware to see if your problem can be solved."

 

Can anyone help me?