OK,
system : xp home sp2
no firewall
one router (nothing change before and after the problem)
browser : IE7 and FireFox 2.x
other security soft : windows defender
other scan : scanned yesterday with avg up to date
scan with windows defender in progress
already tried : the .ini story, clearing logs, proxy configuring
------------------------EDIT--------------------------
I've just finish the re-installation of avast, same problem, the windows defender is finish, nothing new.
-----------------------EDIT 2-------------------------
http://luzftp.free.fr/gest/vracimg/problemeavast.jpghere, a screenshot of the process, the white back, it's firefox who haven't enough resource for displaying this page and the frame, it's a menu who take 30second to draw.
has you can see, ashserv is really CPU time eater but it's another problem...