QUOTE(Scottmotiger @ Sep 23 2009, 11:15 PM)

I quarantined but have no idea what to un-quarantine.
The problem is not that my preferences are set to automatically open files of those extensions with another program. Windows picture & fax viewer simply does not open period. If I double click on an image, it will not load. Additionally, I can't see thumbnails either, all images just appear as icons. And yes, it's set to display them as thumbnails.
I'm not sure what you were saying with the code...
Without knowing what was quarantined by mistake, you'd have to go through it systematically by trial and error unless you can post a list here which might give us some idea. But before going through all the trouble, if you do as Pierre67 suggests, it should reset Windows Picture and Fax Viewer as the default program for the file extensions you choose by right-clicking. Note: instead of "Open With/Windows Viewer", it may be "Open With/Choose Program/Windows Viewer" to get the checkbox to "Always Use This Program." I'm not sure if it also fixes the thumbnail view, but I wouldn't be surprised if the viewer is integrated into the operating system like IE.
The code I gave is the target for creating a shortcut to the viewer. Usually shortcuts point to an executable e.g.
C:\Program Files\Lavasoft\Ad-Aware\Ad-Aware.exe
But for Windows Picture and Fax Viewer, there is no .exe file. If you want a shortcut so you can open the viewer:
1. Copy an existing shortcut and rename it to whatever you want.
2. Right-click properties and copy/paste the code into the "Target" field.
3. Click OK and move the shortcut to wherever you want it (folder, desktop, etc)
If done properly, double-clicking the shortcut opens Windows Picture Viewer, then you can click/drag files to the window to open them. Note, I have Win XP, not sure if this works with Vista or Win 7.