Last time i tried i broke my game and got the dreaded Half T poses.

I have PCEA and FNIS

PCEA:

Simply deactivate the plugin and remove those files:

Data\PC Exclusive Animation Path - 0 - Main.esp
Data\PC Exclusive Animation Path - Argonian.esp
Data\PC Exclusive Animation Path - Breton.esp
Data\PC Exclusive Animation Path - DarkElf.esp
Data\PC Exclusive Animation Path - HighElf.esp
Data\PC Exclusive Animation Path - Imperial.esp
Data\PC Exclusive Animation Path - Khajiit.esp
Data\PC Exclusive Animation Path - Nord.esp
Data\PC Exclusive Animation Path - Orc.esp
Data\PC Exclusive Animation Path - Redguard.esp
Data\PC Exclusive Animation Path - Woodelf.esp
Data\meshes\actors\character\defaultfemale.hkt
Data\meshes\actors\character\defaultmale.hkt
Data\meshes\actors\character\characters\defaultmale.hkp
Data\meshes\actors\character\characters\defaultfemale.hkp
Data\meshes\actors\character\animation\PCEA\
Data\meshes\actors\character\behavior\0_master.hkt
Data\meshes\actors\character\behavior\1hm_behavior.hkt
Data\meshes\actors\character\behavior\1hm_locomotion.hkt
Data\meshes\actors\character\behavior\bashbehavior.hkt
Data\meshes\actors\character\behavior\blockbehavior.hkt
Data\meshes\actors\character\behavior\bow_direction_behavior.hkt
Data\meshes\actors\character\behavior\horsebehavior.hkt
Data\meshes\actors\character\behavior\idlebehavior.hkt
Data\meshes\actors\character\behavior\magicbehavior.hkt
Data\meshes\actors\character\behavior\sprintbehavior.hkt
Data\meshes\actors\character\behavior\stagger.hkt
Data\meshes\actors\character\behavior\weapequip.hkt

----------

First, if you have the FNIS Creature Pack installed: Open the Generator and press "De-Install Creatures".

After that, remove the following files or directories:

• Data/FNISspell.esp
• Data/Meshes/actors/character/animations/FNIS
• Data/Meshes/actors/character/animations/FNISBase
• Data/Meshes/actors/character/animations/FNISSpells
• Data/Meshes/actors/character/behaviors/0_master.hkx
• Data/Meshes/actors/character/behaviors/mt_behavior.hkx
• Data/Meshes/actors/character/behaviors/FNIS*.hkx
• Data/Meshes/actors/character/characters/defaultmale.hkx
• Data/Meshes/actors/character/characters female/defaultfemale.hkx
• Data/Meshes/AnimObjects/FNIS
• Data/Tools/GenerateFNIS_for_Modders
• Data/Tools/GenerateFNIS_for_Users

The FNIS author has detailed uninstallation instructions on his mod page.