Hi!Looking for help

My Morrowind and much beloved characters plus mods got buried inside a semi-dead old PC just around the time Skyrim came, and I never took the time to dig those files out but jumbed into the new game. Also my disk for Morrowind was old and scratched , so when new to Steam and saw Morrowind Gothy on a flash sale I got it on Steam thinking I could allways return to it that way for sure ...

However later i heard Steam does not support modded Morrowind well and you have to do tweaks to allow it at all : and I had plenty of mods, used MW script extender and had managed my saves with Wrye Smash etc.
And by what I also later learned Steam is "jealous" of it′s games in a way that if you have a game on Steam, it will usually only run it through Steam ?

So what I′m asking is :

-Firstly, before trying wake up or salvage the old PC to dig my old games out- is it still possible to run a separate Morrowind disk install on the same PC Steam is on, and if not possible to be run when installed on main PC, run from a separate hard disk maybe ? ( - sry my english, not native, not quite sure what it′s called- separate harddrive or hard-disk maybe?)

- Secondly, if that is not possible with MW still installed on Steam, is it possible to uninstall my Steam MW version and install old disk version on my PC and use it without Steam interfering when I try to play?

- thirdly, if neither is possible, is there a way to get back to playing a modded Morrowind and use old modded non Steam saves with Steam MW , (I know theoretically from Skyrim that moving the data files to Steam folders would propably have the same structure as MW ) or is modded Steam version only viable with new games? Also can I use Wrye and Script extender with Steam /use old saves that had been using those?

Thanks for any help in advance

Actually, modding the Steam version is not that hard at all. You just have 3 things to do:

-install the game outside Program Files or Program Files (x86). Normally, Steam games go to Steam folder, so people had to move whole Steam installation. Fortunately, not that long ago Steam allowed to create game folders outside Steam folder, anywhere on the hard disk.

-you have to re-date the .bsa files. BSA files are kind of archives, that the game stores all resources like models and textures. When using texture replacers, the game looks for a file that has more recent date-stamp. But the files of Steam games get dated by the moment they get downloaded, so most replacer mods, that came months and years ago, just don't work. Fortunately (again) there's a fix for that - the Morrowind Code Patch. It fixes a lot of thins that are not possible to fix through a normal plugin file.

-if you're going to use MGE (Morrowind Graphics Extender) you'll need to disable "Steam Community In-Game", otherwise the screen will be black after launching the game. You can disable that feature in Steam per-game, no need to disable it globally.