My OS is Windows XP
Me too, XP PRO SP1
Avast Version 4 (latest)
Which number?, please, the last is 4.1.315 18th Dec 8:46 (GMT -3)
No other anti-virus protection
Not even in the past? I mean, one that you already desinstalled?
A pop up window that said code was not valid
Why donĀ“t you re-register Avast Home?
English
Today, a new version of avast! will be released at 10 languages!
The firewall that is in XP is being used
Me too, not seem to bring trouble, anyway, you could make a test disabling it
Spyware block is in use as well
Which program?
Anyway, Walker's suggestion is very good...