Aero disappeared please help!!!!

Hello all,

For some reason my windows aero setting has disappeared. I have
searched everywhere in the control panel and such and could not find it.
I have looked online for help and nothing has helped me. The only thing
that i have done differently with my computer in the last 24 hours was
plug in a projecter to my laptop which im assuming is what messed up my
settings, but i am just not sure how to get it back to what it was like
before. Also, for some reason sound won't play from online (like a
youtube video wont play noise) but if i play music from my windows media
player it plays perfectly fine.... I have no computer education, but i
do know my way around my computer so if someone knows how to help me fix
my problem could u please reply.

Thank you


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chris2212