Icon thumbnail problem & can't change desktop solid color background

My desktop background became solid black colors and can only select from solid colors.
Even if I select image it still shows solid color and thumbnail of image in
win7/personalization does not work. (look at image 1 below)

another problem all folder, video and image thumbnails dont work (look at image 2 below)

and some of folder sometimes shows black square on it (look at image 3 below)

All these happened after taking word document from usb my flash drive.
Because those word documents are distorted in another computer
and their extension was .scr and i assume this may cause all these.
but I use Eset Smart Security 5 and no warning and after I scanned pc in
safe mode with Kaspersky 2012 and it found nothing.
I tried Malwarebytes and Spybot - Search & Destroy.
I also tried Combofix 4-5 times and it deleted some file but
problems are still present please help me I want to solve problems
without formatting..

My system:
Windows 7 Home Premium (Activated, not a copy license)
Nvidia Geforce 9600 GS driver is updated.


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