Dell volume buttons crap out

[housenuts]

Hi,
I got an Inspiron 6400 lappy.
Starting this summer the volume control buttons on the front of the laptop just stop working at times.

They'll work fine, and then inexplicably they stop working. To be specific it's the volume up and volume down buttons. It's what I use primarily to adjust volume so it's really annoying when they stop working. So far the only way I've figured out to get them working again is to do the Windows System Restore.
So when they stop I backtrack through Sys Restore a couple days and they work fine again. This has happened about 6 times. Now for the first time, volume up works, but volume down doesn't.
I'm really confused.

Anyone have any idea what might be causing this and know any fixes? Constantly system restoring isn't ideal.

thanks