I am assuming you had an old character and an old world and your old character ran normally.

Start the old character in the old world and see if he or she runs normally. If so, your game installation is probably OK and the problem resides in the new character or new world file. If not, then your game installation may have gone south or you may have a hardware problem.

Quit, then start the new character in the old world to see if the new character runs normally. If so, the new character file is probably OK and the problem may reside in the new world file. If not, your new character file may have gone south.

Quit, then start the old character in the new world to see if the old character runs normally. If so, then the new world file is probably OK and your new character has gone south. If not, your new world may have gone south.

The whole idea is to get a known working model, hopefully your computer, your old character, and your old world. Then replace one part of the working model with one part of the non-working model until the working model no longer works.