When at the mainmenu its making noise from inside the computer, possibly the harddrive. Start the game that noise ceases.
At the mainmenu buttons remain half-obscured under the decoration, not appearing correctly. Like you see text of the button but part of it is under the dragon sculpt thingy at side of screen.

Once ingame it causes cooling fans to blow to maximum after few seconds, becoming very loud. I searched for config file to tweak manually but could not find any, where is the config file supposed to be ?

Is it supposed to run so loud ? Have computer with Intel i7-6700HQ Cpu @ 2.60GHz, GeForce GTX 1060, 16 GB RAM, 64-bit Windows 10 Home, 1920 x 1080 75Hz monitor, Graphic driver and Windows up to date.
Asking since the game is meanwhile so old it has no reason to put this machine into overdrive mode like that.

There is 'no string' overall the skill-tree. As far ive read people managed to get rid of those via turning off tutorial, mine is disabled but still persists. What to do for getting rid of seeing those ?

i have managed to get rid of all issues.
run game as admin + in windows 7 compatibility mode, and under settings clicked default once that solved the performance problems.