system crash when I use the Spotify webplayer in Firefox

Hi,

I am ruing Ubuntu 14.04 on a HP ProBook. I encountered a system freeze twice, when suddenly everything started to be very slow, then unresponsive, and after a few minutes I couldn't even move the mouse any more and had to do a hard reset. After that, everything fine again. Both times I was using the Spotify Web Player in Firefox, which I only did on these two occasions, which makes me think that the problem must have something to do with this. Otherwise I wasn't doing anything out of the ordinary - LibreOffice, some PDFs.

Might be of relevance (though I'm not sure): When I installed Ubuntu on the Probook, the sound didn't work and I fixed it by editing into /etc/modprobe.d/alsa-base.conf as described here https://bugs.launchpad.net/ubuntu/+s...r/+bug/1536948.

But any other occasion where I use sound on the computer (watching movies etc etc) everything's fine.

Do you have any ideas what could have caused the freeze and where I could look for a solution? Thanks.

I'm a newbie so please be patient.

Best, T