Yesterday I tried to map control-alt-w to open chrome. It didn't work. Research showed that Nvidi G-Force experience was the cause.

To fis:

• Open systray
• Right click on the Nvidia icon
• Select NVIDIA g-force experience
• Go to settings (cog in top right hand corner)
• Look on left hand side for IN-GAME OVERLAY
• Move the toggle to turn it off.

All fixed!