How do I change my task bar back 2 normal?

I was downloading something when suddenly my task bar & other things changed. u kno when ur trying 2 exit this file or window u have 2 click the x thing??? before the style was different & now it's all weird. Wat shud i do??? the computer im using rite now is windows premium 7. im not sure if that's wat it's called. it's the newest version.i bought this computer last year so i don't want it 2 be damaged already.