I also just had the same problem. My left-click button on my touchpad is now acting as a right-click button (and the right-click still as the right-click). I've tried uninstalling and reinstalling new Synaptics drivers several times.
I've tried HP support chat twice, and they were not helpful. I then tried calling HP, but my warranty is up so they want $60 for 3 days of support, but from the tone of the guy on the phone, it sounded like he was not going to be helpful either.
I have a small USB mouse in the meantime, but any suggestions on how I can fix this on my own? I feel like it's something funky with Vista, as the left-click button working fine before and technically still functions, but now as a right-click button.