I've recently reinstalled my L420 using my own disk (recovery partition got wiped) and since then I'm having trouble with the volume meter or others call it on screen display volume indicator.
Almost every time that a sound is played by the computer it pops up. Even when the sound is muted. Screenshot is below:
It's almost identical to the problem described here but I don't have an external monitor attached.
I've tried using the update from that page, but issue is still persisting.
According to our community user, it turned out that the audio drivers hadn't been properly accepted by Windows.
Please reinstall the Audio Drivers and it should re-appear that it's fixed the problem. If you'd like to download the driver please click the link in table below or alternativelt you can also go to the Lenovo Support site which may have more latest drivers.
Audio driver for Windows 8 (32-bit, 64-bit) - Desktops, Notebooks (Windows 8 Inbox driver) ... Learn more
Windows 8 32-bit Windows 8 64-bit
Realtek High Definition Audio Driver for Windows 7 (32-bit, 64-bit), Vista (32-bit, 64-bit), XP - ThinkPad ... Learn more