so as the title says, when i try to turn up the volume on the adventure map screen, it constantly opens the quest log.
I checked the keyboad shortcuts and that is Q by default. pressing Q does nothing, so i assume somehow my keyboard volume wheel has become switched with Q. no idea how this happened. anyway, is there a way to rebind keys?

Edit: i also have the HD mod installed and Horn of the Abyss mod, the game would not launch without the HD mod.

Game do start without HD+ mod (or what is become now - HeroesGL mod which one HD+ based on now).

Media keys can work as Q, but that shouldnt affect Q key. Cant say for HD+ mod. Ideal way is test clear game separate HD+ mod separate.
Looks like for both issues you have issue with some steelseries app (which one are not part of the driver even if it come with it). Maybe uninstall steelseries apps and drivers, let windows reinstall it automatically (restart) and try again.

You will lose ability to reprogram this keys (or probably steelseries app useless at all?), If you want that install later this app separately - and configure all settings make it less interfer games as possible and maybe add Heroes as exception if that possible. Still media keys itself should keep worked cause default schema and media keys are part of build-in KB controlelr (and Windows OS hot-keys system), even if OS download non-steelseries driver.

*it can be any else app like it. From mouse. Even camera. Especially if t have overlay dll injected to games (and sometimes player even cant figure out that because there is no actual visible overlay)
MSI Afterburner for example. Although RivaTuner RTSS should be ok (and this is not related apps).

The keyboard is a steelseries apex 7

I didnt actually have any sofware installed for the keyboard and it shows up on the device manager as a 'Human Interface Device ' rather than a keyboard. anyway i tried unistalling/reinstalling drivers to no effect. I downloaded and installed the software for it, which is called Engine GG.

its mostly just a shop with the ability to tweak the keyboards colours and setting up macros which i dont think will help.

I unistalled the mods, and launched the game fine. Weirdly rolling the volume wheel now effects a different key, E, the end turn key.

no other game i play has this issue, i think it is something to do with Heroes 3 itself.

Game can get own specific issues with that indeed. That fact media volume didnt worked as it should is fine for such old game, that fact it can work as main KB button is also normal. And most likely if tht happen - cannot be fixed.

Only un-normal here if [Q] or [E] itself didnt worked (which one are not cool IMO, for me it is enough to call partially game not working). Or if game not started.

In that case it is opposite HD+ mod or HeroesGL can help. Verok's games wrappers wrap not only ddraw\d3d to openGL, but also dinput (and for some game dinput->xinput partial support).
Also, Verok's opengl wrappers make games work always in windowed\borderless windowed mode (so HD+ mod based on it also always windowed now). If there is some Overlay-app launched it can be more compatible with Heroes if they are in windowed mode.
Issue can be from 'exclusive mode' (from HeroesGL .ini settings) on or off.