I've looked for this elsewhere and found some reports of the same bug but no solution except it might be linked to Dawnguard... Equip spells on both left and right hands. Try to cast LEFT hand only and it doesn't work. Character moves hand slightly but no casting. Right spell cast works fine. Dual wield swords, activate left hand and left sword blocks as expected. Attack with right hand and ALWAYS does power attack, regular attack not possible. Any fix? Can I safely uninstall Dawnguard after I've visited the fort? Do I need to load from before visiting Dawnguard, then remove?