DOOM 3 is fully compatible with Win10. I'm not using any compatibility options.
- Have you installed the two patches - 1.3 & 1.3.1?
( I also have a mod called Extreme quality which I believe I installed some years ago. I don't recall which
site I got it from though.)
Main Doom downloads page -
https://www.fileplanet.com/31854/0/section/DOOM-3
- This patch looks to be an update of the official patch, and is cumulative. It may be a better option
at this stage than using the original 1.3 & 1.3.1 patches.
http://www.moddb.com/games/doom-iii/downloads/doom-3-131-fixed-patch-v2
[EDIT: I thought DOOM3 was not affected by the following, but because of your 'log in as admin' error
I decided to have a look at the disk, and it does have the secdrv.sys driver used by SafeDisk.
However, I am not using a noCD, so the 1.3.1 patch may have disabled the DRM ?
EDIT: again - I have a note in my archives that says patch 1.3.1 does remove the need to use a fix .]
- Regarding many other older disk based games....
MS has created a major issue with Win10 and older disk based games that use SafeDisk copy protection.
I have more details on MS's DRM Blocking in my post at --this thread--
(I also have notes regarding more 'traditional' DRM issues in that post.)
- THIS - site has noCD fixes for most games.
.