Click on links to some websites and just get Error 2 (net::ERR_FAILED): Unknown error.

Happens in EI7 and Chrome. AVG, AdWare, Spyware Doctor don’t touch it.

Any advice on how to fix it?

Preferably free solutions

Does this help?

Did you try Ad Aware and Spybot from Safe Mode?

Unfortunately not. No rogue network adaptors and no CA antivirus installed

I didn’t try safemode but neither recognised any threat

It doesn’t look like a threat but some additional layer of defense. Normally browsers ignore error conditions as much as possible, just not displaying things that don’t download correctly

sfb – won’t let me connect to gmail or various other sites. Bl00dy nuiicence.

I didn’t try safemode but neither recognised any threat

Try from Safe Mode. Some nasty little malware hides itself in normal mode and won’t get detected.

Will try that now

Have you tried using Firefox? With the Web Developer add-on?