I do not recommend Norton. It’s incompatible with avast (and AVG).
AVG free is incompatible with avast in Windows XP. AVG 7 is not incompatible at XP.
Suggestion: avast is better. To a backup (on-demand, not resident) scanner, use both on-line scanning and BitDefender Free, AntiVir Free, F-Prot DOS (free). :wink: