Like many of you above, I had a bad VOL + button - it was not responsive. I dealt this with for 6+ months (used another remote to control volume....), was close to throwing it out, then I read this thread and another on the Logitech forums
Here is how I repaired my remote (took less than 5 min for whole process)
1) Removed battery cover (gently remove with hands - apply pressure on the indent to release the tab)
2) removed the two screws (one at top of remote and the other beneath the battery)
3) Then there are FOUR locking tabs at midway through the top curve and the bottom on either side of the remote - near the "1" and the "3" and on either side of the screen, respectively. Getting these tabs to unlock is a pain, and it's accomplished by pushing rather hard with an object against the LOWER part of the remote case. I recommend doing it with a very small screwdriver lodged into the groove.
4) Once opened, I simply took a pencil eraser, cut off a very small, thin piece (just enough to cover the metal contact for the vol + button) which becomes a bridge between the rubber knub from the top of the remote and the metal contact.
Now, the button works great!