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 inWindows 7/personalization does not work. (look at image 1 below)another problem all folder, video and image thumbnails dont work (look at image 2 belowand 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 drie.Because those word documents are distorted in another computerand theirextension 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 insafe mode with Kaspersky 2012 and they found nothing.I tried Malwarebytes and Spybot - Search & Destroy.I also tried Combofix 4-5 times and it deleted some file but