BTW it seems to be happening only with the internet connection because I am actually able to copy files via SFTP from another PC to the laptop with 7mb/s. Really strange.
Hoping to fix the issue by installing newer software I decided to upgrade from 13.2 to Tumbleweed and followed the procedure described here.
I switched to ‘init 3’ before running zypper dup.
During the upgrade this happened. I rebooted and decided to give zypper dup another try. Again: another failure. Hoping to have the things fixed by installing the packages during the upgrade I gave it another try which ended in a similar way.
Then I thought “I will download the Tumbleweed DVD and install from it, maybe the network installation has some problems”. But unfortunately even the DVD installation fails (it seems again because it needs more RAM).
It seems Tumbleweed installation is not working for this PC any more. I guess I might stick with 13.2 as long as it is supported and in 2017 think again…