windows 7 change look of icons

helo, i install windows 7 ultimate few months ago. have SP1 and all windows updates. few days ago i notice my icon on desktop change its look (look of excel files and some icons are in rectangle) as you can see in screenshot. i didnt change anything myself. why did it change?
i scan it with avast free antivirus, Malwarebytes Anti-Malware and HijackThis and everything is fine.

Brink said:

Hello Juuki, and welcome to Seven Forums.

What type (file extension) of files is affected by this?

For now, you might see if rebuilding the icon cache may help.

Hope this helps, :)
Shawn

as you can see all are icons only .xsl is excel file and .exe are HijackThis and GetSystemInfo4. not all icons are affected just some of them.
i dont need to rebild icons its fine like this all i wont to known why did it change itself? am i infected or what?

Brink said:

See if refreshing (F5) the desktop helps.

If not, then change the size of icons on the desktop to a different size, then back to what you had may toggle it to get rid of this outline around them.

If still not, then restart the computer.

i change te size of icons (holding ctr+scroll wheel-) unzoom it one scroll, outline disappear and excel take a old look. ty man, you gave me internal peace, i think im been attacked by malaware