I have bought HaD2 but I am unable to launch (W10 64bit, home). I have tried restarting the PC but error message is still the same - error code is 0x800F0805. After restarting the windows defender even diagnosed hd2.exe with malware (trojan).

Anybody else having this issue?

yup also had the trojans... And cant install the game.... The installer sais my C disk is full but it has 110GB left

Can we get some kind of statement? I didnt buy just to have it in my library ...

@MattTheFlyer maybe Windows Defender already deleted some vital files or sent them into quarantine.
I would do following steps:
1) remove all remaining HD2 files
2) turn off Defender (or any other anti-virus software)
3) Install HD2 again
4) See if it works
5) If step 4 is sucessful, make an exception for your anti-virus software for the Hidden & Dangerous 2 installation folder

//Edit
Direct Play is activated? See here

I lwill try the Defender exception. I tried that Direct play feature but when I click "Turn Windows features on or off" new, completely blank window open so I can not do anything else

EDIT: Made exception but still not working :-/