I agree with your pervious answers,,it's been Hi-jacked by some crapware.
Occasionally that stuff roots itself into System Restore files,,and makes getting rid of it very difficult because it reloads itself from that location.
If that happens to be the case,,You'll need to Disable System Restore,,then Reboot.
Yes,,that erases all saved Restore Points.
But if they were in fact Infected,,,they were no use to you anyway.
Another possibility,,,SOME of those types of hijackers require a Specific Tool.
If SpyBot and Ad-Aware,etc wont remove it,,,
You'll have to search for the Specific name and find a Tool.
Coolwebsearch.exe /CWS was one example that required a specific Removal tool for quite a while,
CWS Shredder from Trend Micro.
As you can see,,,the Hi-Jack is TO a "security site".
Many,Many "anti-spyware" Sites ARE THEMSELVES Spyware,Hijackers,etc.
They hook folks who are looking around the 'net for HELP,Downloads,etc.
And they Also appear as those Windows Messenger POP-UPS,,,"alerting" you that your PC is infected.
Anyone who clicks the PopUp to see what it's about gets the Bug.
Yep,,It's CROOKED as hell.
And even Sneakier than that.
Point is,,Be CAREFUL while looking around for "Anti-Spyware/Virus/PopUp" stuff.
Good Luck
(Freebies & Known Effective/Popular)
Spybot
http://www.safer-networking.org/en/index.html
Ad-Aware SE Personal
http://www.lavasoftusa.com/products/ad-aware_se_personal.php
Keep them UPDATED regularly.!!!!