HI andrewcsfan1, I understand that Firefox cannot connect to a network after updating.

• Fix problems connecting to websites after updating Firefox

What operating system are you using? Is it XP?

andrewcsfan1 said

My firefox just got upgrade automatically to v36, but the borrow no longer able to connect to any web site after restart. (Chrome and IE has no problem.) I try disable IP6 prefetch and proxy and doesn't help. At the same them, my PC has norton install but doesn't have firewall configuration. As the software upgrade automatically, please provide patch ASAP

My PC is in Window 7, when I posted the original post, I have already tried reboot as well as the suggestion in support site. However, slightly after I posted, the browser resume normal

Ditto. Trying Malwarebytes Anti-Malware now, keep getting an error message: SerVer cannot connect to Firefox, and invalid IP configuration. My wife's notebook works normally on our Wifi internet router proving no changes to ISP or router settings. Epson printer and tablet work normally too.

22Mar in Melbourne AU I have FF 36.0.3 version (afraid to install it on my wifes notebook at this time).

Zero virus or malicious entities found by Malwarebytes, Kaspersky Labs, and Avast.

Still stuck ...Win8Pro 64bit 16gb ram notebook.

Avast quarantined a virus that can't be located: Win32: malware-gen about 10 hours prior to losing all internet connectivity. "Ping status fails" yet every other indicator says I am connected.

Don't know if it is a false positive.

Any brilliant minds out there? Cheers

JayKay, The starting troubleshooting steps would be here:

• Server Not Found Issue in Firefox

However if we cannot find a solution here, please consider starting a new thread with the unique troubleshooting info.

SOLUTION FOUND After a 2 week lockout from the internet, I UNINSTALLED AVAST my internet security program.

Internet access immediately resumed normal operation.

AVAST support tried with about 12 replies and new programs to run, but they never directly responded to my question "did avast block my internet ip configuration"?

Of course the answer turned out to be YES (they did).

Luckily our annual subscription was just coming up in April2015, (this month) so I thanked them for the good things and deleted the account.

Purchased Kaspersky Internet Security for multi-devices in case anyone is interested. Finding it smooth and interestingly enhanced.

BTW once unistalled, I reinstalled Windows8 Pro firewall service, then checked internet access by clicking on the Firefox icon.

All is very well. Jaykay