Try some other browser, like Chrome, Firefox or Opera, all 3 are free.
Next, get RID of anything Norton. Instead, install some other FREE antivirus, like AVG or Avira. Both are much beter than Norton, and are much less resources hungry.
Finaly, Windows XP was beter than Vista, and Windows 7 beter than Vista and need less power than Vista to run. (most computers able to run XP can run 7)
Electro, April 2011