Woops, somehow ended up posting this in the Original Sin forum, forgot where I was when I hit new. Anyway...
Ok, really not keen on trying to continue this at this rate. After originally installing BD (and D2), the next time I rebooted I found my desktop all cluttered and running on the basic theme at 640x480x16 @ 60 Hz. Shrugged it off as a fluke and hasn't happened since.
However now, after not playing BD for some 2 weeks, I decided to get back to it and had the game freeze (in the battlegrounds again, but was just there to sell stuff). Waited a bit, nothing, hit ctrl+alt+del and the screen showed up well enough, hit start task manager, got me back to what appeared to be a normal desktop, everything all right, so went back to the game, which was no longer frozen, left the battlegrounds, saved, quit and rebooted, just in case.
Well, upon reboot I once again found myself with the display settings in the same state, so once again had to get everything back in order, place things in their right place on the desktop...
What gives? I do just see a warning when going into the game, can't see what it says but assume it's something about changing display settings for compatibility with the game... May it be that doing that, possible also in conjunction with alt-tabbing at some point, si messing something up and causing this or...? (Still, I play some other old games and never had this happen before.)