TrackPoint buttons gone haywire

[dako]

Help! My T30 has been trouble-free for 3½ years, but yesterday the buttons for the pointing stick went totally awry. Normally I disable the touchpad and switch the buttons for left-handed use. All of a sudden I lost most functionality for the buttons. When they did work it was sporadic and only partial - e. g. they would highlight or push a button but not actually select. I managed after much effort to get to the mouse driver in Control Panel (I'm running Windows XP SP2) and switch to right-hand orientation but this didn't completely solve the problem. When I'm lucky, I now can get the left buttons to work as primary, but using the right buttons even once throws everything off again and nothing works, or else the left buttons work sometimes as secondary, the right buttons do unpredictable things, I have no primary buttons, and it's a huge struggle to get the left buttons back to primary in Control Panel. I uninstalled the existing UltraNav driver, tried using the Windows driver, and then downloaded and installed the latest UltraNav driver from the Lenovo site and updated my BIOS and all of my other drivers, but the problem has remained the same in all cases, whether the T30 was connected to a port replicator or not, and whether the touchpad was enabled or not. There is never any problem moving the cursor. So I am reduced to using a mouse for full functionality but I really need to get the TrackPoint working again. Since all of the buttons do have some effect sometimes this seems more like a software issue than a hardware issue (I hope), but I'm not sure. I'll appreciate any insight and suggestions.