brainaches: ...I start to gradually lose HP points until they drop to zero therefore killing the witcher. The problem appeared when I have updated WII to EE and started a new game. Is there a solution for this bug?
That's probably because you're playing in Dark Mode and equipped a weapon (steel of silver) of one of the Dark Mode sets. They're cursed and as long as you don't wear every part of the set, the sword will drain your health.