How odd, the very instant I clicked on this topic PPRuNe told me the site was too busy and to come back later and my pooter was simultaneously probed by both a StackBo DNS and a Slammer worm sniffer. Coincidence?
I had a problem similar to this a year or two back. I stopped the pop-ups in a similar way to those recommended above but was left with six porno cookies that would not delete in my Temporary Internet folder. You could get rid of them but they always reappeared when you rebooted. Nothing could work out what they were and in the end it took a disk reformat to clear them. Watch out for the porno e-mail swarm. I got up to forty or fifty a day for ages.
I also discovered that one of my disc partitions had shrunk by 50 megs. There was evidently a hidden file that was taking up the lost space. That was when I became seriously interested in firewalls.
**************************
Through difficulties to the cinema
PS: Port 1434 has been probed 17 times while I've been on this topic - that's a fairly massive attack, especially as I'm on-line in full stealth mode with all shields up and theoretically invisible except to the site I'm connected to. 61.233.16.97, you're a very naughty boy. I shall report you to the thought police.