Was this Pop up from the Windows yellow shield that can show up on the bottom tray by your clock? Their were some new windows updates that came out on Tuesday July 11th. You should only get any windows updates from 'their' web site. Otherwise, maybe this was spyware "ad".
Just got a pop up last night that 2 updates were ready for my computer...did the update..but then it said security upgrades are available with SP3..but you need to have you original cd or you can use the website to continue..BUT, do I HAVE to take that??? I use Firefox and scan everynight with Ewido, Trend Micro and Adaware..what is the "Security' upgrade that is in SP3??