Thanks for the advice.
Unfortunately this doesn't seem to be the problem. OR at at least just a a part of it.
Deactivated my antivirus und my firewall as well, but the setup still loads like crazy and can't be forced quit either.
Another thing i've noticed, when i attempt to install it via the SD central, there are two greyed out buttons, above a "pause" button and a activating button "below".
Because i never used the new SD central for the former betas, i'm not sure if that's a bad sign or not or how it should regulary look like.
Every beta before or other SD games always worked like a charm, i didn't change anything substantial hardware or software-side in the last months, so i'm pretty clueless.
Any further advice
?
edit: i reinstalled SD central. But now when i click install the above mentioned window won't even open itself anymore, just loads and loads like when i double click the setup.exe manually.