Hey VampirX4 - I checked your specs and you should be able to run the game with top settings with no problems.
Have you tried setting all the visual settings to minimal, restarting the game and trying again?
Other than that the only recommendation is restarting computer and trying again, and making sure nothing runs in the background.
Hardware wise - nothing can really go wrong, got to be something on windows side - with some program running in the background causing this.
The only other thing to check - if you have changed any customer performance properties on your video card, try to reset it to default - if you played around in Nvidia or ATI Catalyst control pannels.