How to get laptop back to normal after downloading and also persistance message in yahoo search wondow?

i downloaded windows explorer 8 after thinking it woukd be faster etc ..since then problems,..stopping freezing icons coming and going long waits for email etc ..i have windows xp ...what to do??? i looked in remove prog but cannot understand what to remove to get ris of it.. sorry not too comp literate..also on email i get 'candygram' in yahoo search window..stops things