can't change the size of items on this display on windows 8

Hi,

I have a dell Inspiron N5110 with Windows 8.1.

I'm not sure what happened but all of a sudden the size of items on my desktop are really big and in control panel I get this error - 

"can't change the size of items on this display"

any idea how to solve the problem?

thanks.

p.s.

I tried re-installing both Nvidia and Intel graphics drivers but it didn't help.