Windows 7 gadgets not displaying properly. Black squares or don't appear at all with blue exclamation marks next to it.

Question

My gadgets on Windows 7 have suddenly stopped working properly since 2 days ago. I have tried:
System restore
UAC is ON
cmd scannow (no results),
tried the registry thing, didn't work either.
How to fix this? 
That's how it looks...
http://i15.photobucket.com/albums/a360/Katjushka_/fuckedgadgets.jpg

Answer 1

I do not personally recommend the alternate work-around of deleting any registry keys and/or reducing any of your internet security zones.  I have found fixes to it in a more secure way below, as I consolidated and cleaned up countless snips from many
forums all over the place (cited sources of where I could remember I found the concepts); Here's my research notes: full disclaimers, hold me harmless, and always backup first!
IE11 BUG:
This bug in the public release version of Internet Explorer 11 (aka IE 11 aka IE11 RTM gold release) causes Windows 7 Gadgets to bug out.
Specifically, with IE11 installed on Windows 7, due to a bug in IE11, increasing DPI past 110% triggers SOME of the Gadgets to glitch, bug out, completely disappear, etc.  This bug can be worked-around and "fixed" by modifying its Sidebar gadget.xml
<autoscaleDPI>...  described in detail below.
This bug is irrelevant to Windows 8 / 8.1 because Microsoft removed the beloved Gadgets entirely in Win8 due to so many third-party evilware writers embedding malware into their "free" downloaded Gadgets (note to the best of my current knowledge,
using the standard Microsoft Gadgets included with Windows 7 are all perfectly safe).
To reiterate, notice the following Microsoft article is only talking about potential malware in third-party downloaded Gadgets, and specifically I do NOT see where it mentions any problems using any of the official Microsoft build-in Windows 7 gadgets, cited
from:  http://technet.microsoft.com/en-us/security/dn261332
BUG FIX:
Option 1: Set DPI back to 100% Smaller Fonts (default) or maximum 110% and the Gadgets come back to life and work fine upon relog.
Option 2: If you need greater than 110% DPI, and want Gadgets to work, then... For each broken Gadget, modify its protected file:  gadget.xml   (as detailed below).
FIRST, TEMPORARILY CHANGE DPI BACK TO 100% (DEFAULT) JUST SO YOU CAN SEE THE HIDDEN/GLITCHED GADGETS IN ORDER TO FIX THEM.
Note as a side-effect, after the "fixed" Gadgets in question come back they may look smaller in comparison with the ones that were not affected by the DPI bug (because this fix locks their DPI at default 100% whereas your others are dynamically changed).
Located in:  C:\Program Files\Windows Sidebar\Gadgets
Inside that folder, find the glitched Gadget you want to fix, go into its specific folder, and edit its gadget.xml, Remove the following tag completely:
<autoscaleDPI><!--_locComment_text="{Locked}"-->true</autoscaleDPI>
Deleting that tag from the gadget.xml file resolves the issue even if the DPI is set to 125%. Setting the tag to allow autoscale doesn't help.  BE CAREFUL not to leave a blank line!
Concepts:
1. Make backup of effected gadget.xml somewhere
2. Task Manager -> End Process of "sidebar.exe" to unlock all Gadget's files
3. Take temporary ownership and give yourself RW permission to modify Gadget's files
4. Put all Gadget file ownership and RW permissions back to "TrustedInstaller" for security
5. Change DPI and relog to relaunch Gadgets
Details:
From Security Tab in Properties of file you want to change >>Click Advanced >>Select Owner >>Click Edit >>Click Other users or Groups >>Click Advanced >>Click Find Now, make yourself owner, then add write access for yourself.
Launch NOTEPAD or similar editor as ADMIN, to modify the gadget.xml file (the folder structure itself is still permissions-protected, but I strongly suggest you leave that alone and just use admin for editing this one file this one time)
Put Ownership and all permissions back to what they were (First, set read-only for everyone EXCEPT leave RW alone for the TrustedInstaller service, and THEN set Owner back to TrustedInstaller).
NOTE: TrustedInstaller does not exist in the "visible" users and groups as it runs as an NT Service.  Don't panic. To restore its special ownership:
    Right mouse button click on the file and choose Properties
    Click Security tab
    Click Advanced button
    Click Owner tab
    Click Edit button
    Click Other User or Group and type in:  NT SERVICE\TrustedInstaller
    Search and click Ok on all dialogs until all property dialogs are closed etc.
Cited from http://blogs.msdn.com/irenak/archive/2007/01/30/sysk-277-how-to-bring-back-the-trustedinstaller.aspx
Double-confirm you set all regular users and groups permissions are reverted defaults back to what they were (read-only), and the *ONLY* Owner/RW is TrustedInstalled, to lock it back down for security reasons! E.G. to avoid future vulnerability!
To test:
I fixed my Clock gadget.xml but left the Calendar alone.  Changed DPI to 125% and relog off/on and notice Clock now works, but yes it looks slightly smaller than the working Calendar Gadget which isn't effected by this bug.  Repeat process for Calender
if you want it smaller to match, but it works fine bigger. Repeat this process for all of your favorite broken Gadgets using IE11 on Windows 7.
Notes:
1.) Personally I view this as a work-around not a true fix, but considering Microsoft officially discontinued Gadgets as mentioned earlier, it's possible this bug may take a very long time, if ever, to be officially fixed.
2.) IE11 also bugs out a lot of other things such as Outlook 2003 spellcheck, and other general software compatibility issues, especially in Windows 7, so it's probable that some or all of IE11's bugs should be eventually fixed in the future - thereby as a
side effect may also officially fix Gadgets some day too.
3.) Other concepts cited here: http://social.msdn.microsoft.com/Forums/ie/en-US/448f9665-c043-48d2-9049-b74131bab7b1/gadgets-not-working-with-ie11-win7-pro-sp1-not-win81-preview?forum=iewebdevelopment
Good luck!