Windows 7 - Background Slideshow is not working

I have laptop w. 7 ultimate somehow background slideshow is not working at all. I right click on desk top>personal>background slideshow>browse>wall paper( from my pic libary)>select all>save change. Window won't save the change and keep go back to solid colors( window default I guess). But If I select 1 pic in my file it will appear to be my back ground.I did cmd>sfc/scannow,won't work. I run 2 different malware and get rig off some bad file. Still won't work check all setting include power option, ease of access...I don't know what to do next some one please help. I'm not a comp. geek just an amature...so please detail if you could thanks.