So I installed Morrowind under C: instead of under C:programs like everyone said, now where do I install the expansions to???? Anyone?

The same place IIRC, where you have the Morrowind directory installed

So I Just under C: It doesnt have to be under C:/Bethesda?

You installed in C:\Morrowind? Then install the expansions in the same place. It doesn't have to be in Bethesda, people do that sometimes for organization reasons but you don't need to.

Once you've installed, the path should be stored in the registry so that the expansion installers should already know that.

excellent.