Left click on Vaio-Z... Anyone else have issues?

I have a z540, a month old, still running the Sony install of Vista Business. About 2 weeks ago I noticed the left click button becoming intermittently less responsive. It started requiring much more pressure to respond, or would take multiple stabs to function. As I said, it was intermittent, and I was thinking that it might be more of an issue as the machine warmed up, as it would often work perfectly when booted up cold.

I called Sony support, thinking I needed an RA to replace the hardware. The tech had me uninstall the Alps pad in device manager, and to my surprise that seemed to fix the problem after rebooting. It work fine for several days, then yesterday I noticed the problem was back. I did the touchpad uninstall again, but this time it seemed ineffective. THEN, while I was workng on something else (programming external keypad shortcuts), the touchpad became erratic and uncontrollable. While investigating THAT problem, I clicked through a couple of different windows and suddenly everything worked perfectly again, both touchpad and left click button. At the moment it is like new again, but apparently some weirdness in the driver affects it unpredictably.

Any ideas on correcting this?

 

It could be something as simple as a speck of dust. One way to try to fix this is to place the laptop at an angle, and then drum your fingers on the casing close to the affected switch for 10-30 seconds.
Alternatively, use canned air on all nearby cracks, but not so much that you freeze it (bad solder joints coming lose can be triggered by spraying with canned air too close or for too long, due to the temperature differences causing tensions).

Other than that, the switch itself might have worn out, especially if you now and then hit or push it hard. Then Sony's repair service is probably the best alternative.