Can't browse web after 5.1.864 update virus database 110101.1

[americanu]

 Until today the program was working fine, but Today avast antivirus updated itself to a new version and a new virus definition.

Since the update i can't browse the web unless i disable avast web shield. also i  can't acces network location or use any aplication that is using LAN unless i turn off network shield.

Internet conection is working properly without Avast.

Accesing LAn resources is not working properly now even witout Avast. My ISP stated that no changes were operated.
No previous antivuruses used.

I'm using windows 7 and windows 7 related firewall.

I've already tried switch on/off the firewall no result.

formating is not an option.  

[americanu]

Uninstalling it with the removal tool in safe mode, and reinstalling a previous version (667 i think) solved the problem.

Thank you for your support

[Pondus]

have you tried doing a clean install of latest version?

[americanu]

have you tried doing a clean install of latest version?

Yep already tried that. same result. it simply does not work with the newer version