This should not be happening...on vanilla Skyrim.
Try to re-install that way, and start a new game. If your problem doesn't get solved, somehting else is the culprit.
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First do a standard uninstall. (Control Panel\All Control Panel Items\Programs and Features-> Uninstall The Elder Scrolls V: Skyrim)
Next, delete your skyrim folder under C:\Program Files (x86)\Steam\SteamApps\common\
Then delete your Skyrim directory under Documents\My Games (after backing up your save files, if you wish)
Then under C:\Users\[Your Username]\AppData\Local\ - Delete the Skyrim folder that is in it.
(You should enable to see the hidden files under windows to delete that folder.) HOW: (View - Options - Folder Options - View - Advanced Settings: Show hidden files, folders and drives)
Go to your Steam folder. Delete the folder named appcache. (Important)
Use Ccleaner after all this (http://www.filehippo.com/download_ccleaner), Go to the Registry tab and hit -
In the Options tab go to Monitoring and uncheck: Enable System Monitoring and Enable active Monitoring
Reboot your computer (Important)
Then install your game again, from scratch. !!!!
*** You don't need to uninstall Steam. ***
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