Several months ago I bought the CD copy of skyrim and installed it on steam. The first time that I played it, my PC told me that it was able to run it on ultra settings, which worked perfectly. A few months ago however our Internet went out for a week or so and during that time I was not able to play the game because steam had been left in online mode. When I was re-able to play it, skyrim moved the play quality down to high settings, however when I played it I was lagging something awful. I then tried to play it on the lowest setting possible and also turned both Antialiasing and Anisotropic Filtering completely off, and it still lags. Does anyone know how to fix this, or at least what went wrong?

P.S. I'm not the best with computers, but should be able to follow basic directions.


PC
Model: Asus Notebook G73Jw Series
Processor: Intel® Core™ i7 CPU Q 740 @ 1.73GHz
Installed memory (RAM): 8.00 GB
System type: 64- bit Operating System
Display Adaptors: NVIDA GeForce GTX 460M


P.S.S. I don't even know if that is the right info, if you need something else, tell me.