I already have Morrowind installed but have just bought the GOG version because I'd like to be able to play it without having to put a disk in. The old disk version (it's the GOTY version) is heavily modded and I would like to use the GOG version with all my current mods. Can someone point me to an advice page about how I can do it? Should I uninstall my current version, install the GOG version then do I have to mod the GOG version? Or is there a simple way to do it?

Thank you for any help advice... :-)

OBTW, does the GOG version include the add-ons (Bloodmoon, etc)?

1) I never had an issue installing the gog version with the the disc version on a 'Puter.

2) how extensively is the existing install modded? If all your mods are just esm/esps + their assets, copying the "Data files" folder to the the "new" install should work fine. But if you used "Morrowind Graphics overhaul" and or other 3rd party utilities/fixes you should apply those first though.

Note: the GOG version also comes with the DLC esps that Bethesda made but you should either clean them or dl versions that are cleaned

here's a thread that may help you.
http://www.gog.com/forum/elder_scrolls_series/morrowind_essentials_important_fixes_wellknown_mods_and_projects

WOW! Thank you. Just the sort of info I was looking all in one place. On my disk version, I have the graphics extender and the usual better heads, bodies, plus a few tweaks I made myself (like Rich Creeper- has 500 000 gold :-) ) So I think your point 2 tells me that I should be able to do and easy transfer from Disk to GOG. I'll start with that I think.
Thank you!

When you get it working, be sure to back up the entire folder onto a memory device. That way, if you ever have to install the game again, or put it on a different PC, you would only have to copy the back and paste it over the new install. Done.

In short; back up the entire game folder, not just the DATA folder. Assuming you wrote down the games install path(hint hint). You could install the game(vanilla) on any of your machines and copy past the back up over the fresh install. This will save you a huge amount of time. Because adding new mods may bork your game. It happens. It sucks. It happens even on skyrim etc. Crap you liked gets changed because there are to damn many things to keep track of. Once you are happy with your modded game, having that backup everytime you need it is a good thing =D