Windows 7: Skyrim stutters every 5 second

I played the game for 100 + hours without problem, then this problem appears.
Skyrim freezes then resumes then freezes every 5 seconds after playing for a few minutes.
I tried re-installing the game, lowering the graphics to low, removing all mods.
This is also not a savegame issue, it happens even in a new game.
Also tried running in windowed mode, did not fix the issue.
I also tried using game booster(to see if a background is causing this).
I also tried running the game in my Windows XP partition, got the same problem.
I do have the latest drivers and patch.
One thing I have noticed is my CPU load goes from around 90% to 30% during the freezing.
Any help is appreciated.

update your card's driver, Direct X and run antivirus and anti spyware. CPU usage going high is normal while playing games.

Let us know what is the outcome.

Have you tried it on a different harddrive? There could be something wrong with the harddrive itself

try defraging the the whole hdd and updating skyrim to the latest patch

The CD drive (if your using one for the game) is currently acting up, reading the scratches on the disk and reply it to the game, making it freeze up.
This could help you a bit, just reply if you still have the problem.

The drivers the patches and dx are up to date, I have tried installing it on other hard drive did not fix issue. Strangely turning on FXAA reduces the frequency of the freezes.
I will try defragging the hard drive.

I don't play skyrim so I don't know whether this is an online game or not but I believe that it is... if that is the case, it could be as simple as your internet having issues or their server and not necessarily you.

This is Memorial weekend so I assume more people are playing online than normal?

It's a single player game AstaLaVista, it does not need the internet either (unless you need to register it to Steam).

I stand corrected then...

You only have 2gb ram, I was getting some stuttering on 3gb ram, soon stopped when I build a new PC with 8gb ram, with all HD mods, never now use more than 3gb ram.