My neighbour asked for help with “something strange on my computer”. OS is Vista. She had installed Firefox (by accident) and apparently it was since then that she’d had strange pop-ups. From the description they sounded like soft-porno sites. The only pop-ups I saw were “Winlogon notifiers” - 6 copies on the desktop, all identical, all relating to “!SASWinLogon”. Deleted Firefox (because she found its Logo “threatening”!) and restored IE to the desktop. Ran A-squared; C Cleaner , Super anti-spyware and Spybot – all of them new copies that I’d downloaded on my own system after I found that her already installed copy of Spybot was behaving oddly. these found only low-risk cookies. Finally Ran malwarebytes anti-malware which found and deleted Trojan “Vundo”. The pop-ups about Winlogon appear to have stopped. Switched off Sys Restore and then on again. As far as I can tell all is OK again – unless anyone can see something I’ve left out!