I have no certain idea what you are trying to ask. "vedeos" are "videos" I assume - as for what you mean by "not found in website" - maybe you mean some of the videos you are trying to view from some websites are not playing?
Install the proper web plugins (Flash, Silverlight, Quicktime, RealPlayer/RealAlternative, Shockwave, etc) to see whatever videos on whatever web page it is you are trying to get to.
As for the the other part - where you don't have aero ro change your bac[k]grounds - that could be all sorts of things. What edition of WIndows 7 are you running? What video device do you have (and how much memory does it have?) Do you have the latest drivers/software installed for that video device?