Black squares on desktop instead of icons

I have black squares being created instead of normal icons on my home screen when new files are created. (Mostly PDF files) When I move the file to another directory (copy or move) they then show with the proper icon, ie PDF icon. Any suggestions?
Running Windows 7 Home Premium on Toshiba Satellite A665-S5170,
See attached image

Shawn,

Thanks ! That did it. Not sure which one worked as I did both and then rebooted and now my icons are back, all nice and shiny

Here is another one for you. I use Firefox and I think since the last update there is an issue with the spell checker in gmail. It shows the last few letters of some words as misspelled even when they are not.... I read somewhere this is a known bug in new Firefox.... but have not been able to find any other references.

Thanks, apologies, should have realized that... was being lazy...
Will do!

Remove (or Change) Arrows on Shortcut Icons Desktop in Windows 7
Start -type “regedit”. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer
Look through the Explorer key and see if there’s a subkey named Shell Icons. If there’s not, you’ll need to create it by
right-clicking the Explorer folder icon, choosing New > Key, and naming it Shell Icons.
Next, you’re going to create a new value inside the Shell Icons key. Right-click the Shell Icons folder icon and choose
New > String Value. Name the new value 29.
Now, you’re going to modify that value. Double-click the new 29 value and type (or copy and paste) the following into the
“Value data” box to remove arrows from shortcut icons:
%windir%\System32\shell32.dll,-50
Click OK and exit Registry Editor. You’ll need to restart your computer to see the changes.

If you want to bring the arrows back, just delete the 29 value you created. You can leave the Shell Icons key in place.
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Black Icons desktop windows 7 -repair-
%windir%\System32\shell32.dll,50 (change from -50 to 50)