In my computer back is it needed windows reinstalled ?

I used windows 7 ultimate. my computer is way too slow and it's meant to be at the fastest speed there is. Also is it the trend micro causing it to go even slower. I liked it better with windows xp. It still freezes and sometimes won't go off a page when you click to go off. it won't load or open a page. then you are on something else and 10 minutes later the page comes up that you wanted before. i just spent 250 dollars to reinstall windows and get the windows 7 put in. so anyone got any thoughts on trend micro. I am also running superantispy free version to pick up the malware that trend might not pick up. any suggestions.
and yes i have been trying to contact the guy that does my computer and i am so pi……ed off with this thing.
