Problem with morrowind interior cells

hey mates, having a major problem with morrowind, just reinstalled it after a long absence and decided to play through, however, whenever i enter an INTERIOR cell, my performance goes to hell. problem list; jerky movement, i get terrible response from my mouse, basically like playing a game at 1 or 2 FPS although fps is not low (worst it gets is 16 or so). most keyboard commands unreliable, with the exception of use, for example, i'll press my equip weapon key and nothing happens, i'll keep pressing and nothing continues to happen, then sorta at random it will work but it may take 10 seconds before that happens and sometimes it immediately puts the weapon away again! jumping all screwed up, whenever i fall indoors its like i'm under slowfall 100 or more (have a constant ring with slowfall 1, but taking it off doesn't seem to change anything)