avastSvc.exe is crashes and blocks internet connection

Randomly, while surfing, avastSvc.exe is crashes and blocks my internet connection.

I have noticed a huge file (+/-130mb) is being created on the folder “C:\Documents and Settings\All Users\Application Data\AVAST Software\Avast\log” when this problem occurs.

To solve this problem, I must close the AvastSvc service (then I get application Error message), and then the internet connection is back.

Can you help me to solve this problem?

Win XP sp3 – IE8 ver: 8.0.6001.18702

Welcome to the forum.
Try a repair of avast! using the add/remove function.
Select avast! then scroll down and select repair.
Reboot your system and see if your problem is solved.
If not, please answer the following questions:
What other security programs are you using ???
Did you have another Anti Virus program on your system before installing avast ???
If you did, how was it removed ???