HELP---My windows vista has changed : (

well i first used to go on my computer and you know in the right corner where you can close restore down or minimize a program it used to be normal like kind of big icons for windows vista type. then yesterday i done Microsoft update and everything on my computer changed the theme turned to power save and the icons on the right corner( restore down or minimize) have all turned different now smaller and rubbish. i tried to change theme and stuff like that to see if it would turn to normal but nothing works.
someone please please please please help or my mum is going to bang at me

thanks lots in advanced

EDIT: it goes a bit slow as well, i have tried ad-ware but nothing changes