Freezing and Lag and more Issues

[FeralFantom]

So I played fine with no bugs at all. Put several hours in, was about level 33. I decided to start a new save to do a magey character. That character was also progressing fine until I got to riverwood, accepted the golden claw quest, and went to fight the bandits. Starting with the ones in the tower my spells were lagging a bit until by the time I got to bleak falls barrow and killed the first few people inside It would lag for 3-5 seconds then be back but to the point where I wasn't even dealing damage, just lagging, then it froze and I had to close it. Tried this from a save point several times same thing, noticed if I just cast the flames spell at nothing it worked fine, but as soon as it hit an enemy the lag appeared. I abandoned this save and accidentally deleted my first character, so I started yet another one, this time an archer because I assumed the problem was with the spell casting. Got this guy farther, he is level 11 right now, about halfway he stating lagging a bit when firing arrows at enemies. Nothing too noticeable until just recently it crashed with no explanation, reopened it and it crashed again after a minute or two. Reopened again and no more crashes, but now lag just while walking, horrible lag when shooting at things that sometimes freezes the game, some sound effects just stop happening and buzz noises occur, when I try to pick the necromancer's robe off this dead guy it freezes unfailingly each time. Also these freezes are so bad I can't fix them with task manager, have to manually reboot. I am at a loss here, looked around a lot couldn't find anything relevant. Why would it just randomly start after hours and hours of perfectly normal play?