Solved Sound has disappeared

[RoWin7]

I opened the case of my p6-2020t HP to add a video card. When I closed it and turned it back on, the sound was gone.

Mobo has onboard sound, Realtek High Definition Audio, dated 2011, driver version 6.0.2.6531

Device Manager says it's working fine.
Speakers are turned on and plugged in.
Sound icon level in systray is above the bottom. Mixer shows everything is on, but doesn't move.
I hadn't changed anything.
System sounds don't play either.

I'm stymied.

 

[iko22]

Hello,

Sound drivers were installed before the sound was gone?

Are your Speakers plugged into Front audio jack, or rear audio jack?

If you open Volume Mixer and then play a sound, does the Audio levels go up and down?

 

[RoWin7]

Always had drivers. The computer is about 10 years old.

Ooops, didn't think about front jacks.They were in the back, plugged into green "out" socket. Just plugged them into front and they work.
Mixer moves and I have sound again!!

Could I have touched something inside when I installed the graphics card? My flashlight was wonky and fell into the case a few times, and the light kept going out. But I don't know what to look for.