These are the only informations you have posted:

So here are my questions for further details:

  • Which WinXP? (32/64 Bit - which SP)
  • Which avast-version? (Pro, Internet Security, Premier)
  • Which program version (2014.9.0.2013 is the latest)?
  • Other security related software installed?
  • Which AV-Program was installed before and how was it removed?

DJBone