Promised screen grab is attached here...

Do you have any Kaspersky software installed on your computer.

If you have then contact Kaspersky support and ask them about this.

Thanks for the reply. No, I don't have any Kaspersky software. It's a strange accidental redirect, given the current news. I tested it again last night, and the glitch was back; redirecting from "yahoo.com" to kaspersky-labs.com. Gone again today! Any other ideas?

Goto your Preferences -> Advanced -> Network settings and is there anything written in there? could also be a rogue extension.

Goto "about:support" in your URL bar and then click "refresh firefox" that should get rid of any kinda of odd config.

If it persists I would check what you have set for your DNS servers and what process daemons are loading on your startup...

Or maybe an advertising blitz by Kapersky? haha

) you are probably right. It's not unthinkable for internet security or anti-virus companies to advertise by hijacking or transmitting viruses.

Many thanks in any case for the reply. Nothing in advanced network settings. I followed your advice and refreshed my firefox. It is no longer happening, so far. It was just a weird thing, probably will never know why this happened.