I think I'm onto something, guys. The trackpad problem has been reoccuring for me, even though I said in a previous post that uninstalling the cypress driver solved my problem (it reoccured a few days later). Like others have already pointed it out, the trackpad would rarely work and even the keyboard would occasionally stop working. A reboot would fix the keyboard problem, but would not necessarily bring the trackpad back to life.
I didn't want to send the laptop to service because I needed my laptop, so I have been resorting to an external mouse. Recently when the keyboard stopped responding again, I tried pushing as many keys as possible and found out that a few would respond. The particaular keys that responded strongly suggest that it is a software problem. The keys that responded were all laptop functions: the "WiFi Enable/Disable key", "microphone enable/disable key" and "camera enable/disable" key.
I have been trying to find a pattern to the seemingly random trackpad and keyboard freezes. It turns out, that the trackpad will work on a fresh boot (and will not die after some time - not even the keyboard), if you disabled the WiFi (the F7 key) just before you turned your laptop off the previous time - so that it stays turned off when the laptop boots up. After it has started up, you can turn the WiFi back on.
I will report back if this solution is not consistent (if the problem returns). I must say that I am disappointed that there are no official Lenovo support employees on this forum, that would look into the problem and the user is left with either having to send the laptop to service (and not having the laptop for some time) or trying to solve the problem on his own.