Hi hope someone can shed some light on this. I currently seem to have two files on my system called SkyrimPrefs and am not sure which one to edit.

The first is lcoated here: C:\Program Files (x86)\Valve\Steam\SteamApps\common\skyrim\Skyrim

and the second here: C:\Users\Win7 User\Documents\My Games\Skyrim

Both files are notepad .ini files. Anyone know which i tweak to improve the settings as seen on other threads.

Thanks for any help and advice.

You want to edit the one in the Documents folder.
The ones in the game's main directories are just the defaults that the game fetches its presets from.
Editing those will just mess up the default values, fail steam file verifications since they are no longer the same, and simply be overridden by the values in the ones in the Documents folder.