When I first tested the newly-integrated Windows 7 gadgets, I discovered that the gadgets disappeared every time I turned UAC off. Well, now you can keep UAC turned off and have your gadgets. Huzzah!
I must warn you, this fix is not for those who don't like to go into their registry. You should probably set a System Restore point or backup your registry before you attempt it. Steps follow below, and are slightly modified from the original for clarity:
1. Open the Registry Editor, or regedit.exe. You can search for regedit in the Start Menu.
2. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Sidebar\Settings
3. Right-click and create a new DWORD (32-Bit) Value called AllowElevatedProcess.
4. Right-click AllowElevatedProcess and click Modify. Set the value to 1. Close the registry editor. Your gadgets should work with UAC off now.
Ah, my one, lonesome, beautiful Weather gadget, how I have missed thee. [diTii.com, thanks Gank!]