If you right click on the shortcut or executable for Notepad (or the DD configuration tool) you can select Run as Administrator. To always run as administrator, right click the shortcut/executable, select Properties and check that option in the Compatibility tab.
The loading screen / main menu background images are in 1024x768, 800x600 and 640x480 resolutions, so until you get into the game it may not appear to be at your desired resolution.
If you don't have any fog of war (a glitch that happened to me once in the disk version when I reloaded an old save and re-entered the Dark Forest to check something; it was fine the first time), you can save under a new name (just to be safe) and replace the shroud.* file in your save folder with the corresponding version from the '..\Divine Divinity\main\startup' folder (or from a different save that has the fog of war).
Different file extensions are associated with different areas of the game;
.0 / .x0 = Ferol (Aleroth, Ars Magicana, etc)
.1 / .x1 = Verdistis, Council Hall
.2 / .x2 = Dark Forest
.3 / .x3 = Black Ring dungeons
.4 / .x4 = Wastelands
Each save is a separate subfolder in the '..\Divine Divinity\savegames' folder.
Under Vista/7, depending on how the user accounts are set up, if you install the game to the default Program Files path, Windows can create separate savegame folders for each user, and then map that folder to the game's savegame folder (so it will just see the saves for the relevant user).
C:\Users\ %account name% \AppData\Local\VirtualStore\Program Files\Divine Divinity\savegames