At last got around to trying it. As it turns out deactivating sound in the launcher didn't crash my user session, but still some weirdness happened: by screens both started to flicker as if switching from one input source to another rapidly, but I kept getting a black screen and that's it. After a couple seconds i got kicked back to desktop, but the game didn't crash, so I could alt-tab back into it.
playing without sound is not exactly desirable though. any other ideas?
Edit: Perhaps i should add that the PC is by now around 12 years or so old, so hardware out of spec isn't exactly a surprise. but alas, back in the day I built this thing to have a system I would not need to put money into for a good long while - and aside from a couple power supplies and a set of RAM, that did indeed work out as intended.