Troubleshooting

Photo from spring 2008. Me with dog Aurora.

Our iMac is acting strange.

The volume is constantly lowering itself.

I can't press shift, command or alt by themselves. I can press command+Q or shift+A for instance... but I can't hold down command and select files for instance... or I can't hold down shift and scale an image properly in photoshop. I'm going nuts! Has anyone experienced something like this before?