Originally Posted by Sean_W
Make sure it's activated in the "Hardware Drivers" and then just reboot.
Where is "hardware drivers"? When I searched for that term in "Ubuntu Software Center", it displayed something called "jockey" (and lots more apps) and asked whether I want to install it. Is this what you mean?
Woops, I guess not. I found "Hardware Drivers" under another desktop menu. But when I selected that, it only showed the old 173 driver, plus another one called "current" (with 173 being marked active/installed). However, that entry gave no indication what version it corresponded to (not very helpful). Fortunately, after I selected it and rebooted, I appear to have the new driver working. Thanks!