Trackpad is functional during boot - afterwards not

[emem]

Hi folks,

I've got a Fujitsu notebook with a trackpad and a trackpoint.
I run Mint Isadora KDE and got the issue stated in subject.
If I have filled my credentials and hit the enter-key the icon-fading second bootscreen appears.
There my touchpad works fine. But after the KDE-Desktop is loaded it stops working.
The trackpoint is still doing his job. Event the left and right touchpad-keys are still functional.
Only the pad itself does now nothing if I touch on.
Is there anybody who has an idea about the reason of this behavior?
Trackpointing makes me mad...

Thanks and best regards,

emem

[emem]

Has nobody an idea where I could look for?
I'm new on this OS and become crazy by these hundreds of config- and logfiles...