After replacing a faulty ADSL modem, the main PC worked fine, but the wireless laptop would either lose its connection to the internet, or websites would be very very slow to load.

A quick way to test this was to ping google.com.au.

Sometimes ping would say something like “connection unavailable” or it would timeout, or give return times of over 2000 ms.

I know ping return times are normally between 150 ms and 400 ms, so something is wrong.

The wireless signal strength is excellent.

The laptop is a fairly new core2duo, and it hasn’t had these problems in the past.

As I’m taking to the owner, I mention that Norton might be interfering somehow… its expired, so I’ll probably need to remove it.

He says that Norton shouldn’t be running. He had a mate tell him Nod32 offered the best protection. So this friend installed nod32, but couldn’t remove norton…

Ahhh, I’ve been here before… back in the days before dual-core CPUs.

So, it looks like running 2 antivirus programs doesn’t appear to slow down a multi-core CPU much, but it does drive the internet connection haywire.

Something to remember for “next time”.