@Helloworld
It's working fine after a reboot.
I did fail to back-up my previous OS4.0 installation, resulting in the loss of the look that I used. My Workbench basically looked like MacOS did back in 2005-2007. I got that setup from another user back then. No clue anymore on how to get that back, though I have an older backup with some of the icons.
I don't have onboard sound, but a dedicated soundcard.
Still no clue what actually fixed the issue, but after all the updates it boots faster than it ever did.
Now trying to find where to download Timberwolf.
Anyways, thanks to both you and Raziel
.