Hi,
I just did my 3rd major sytem recovery this year from spyware. The last is almost over as am still plucking adware out of the registry.
I run Spybot S& D, had been running that with Norton's Sec, Norton's Anti Virus, Ghost Surf, Noadware( no good), Trial versions of Bullet proof ( I like BP) and Spy Begone, and a few other softwares. In essense, I found out that much of this software is not what it promotes as I had the highjacking of IE as you , plus a major takeover invasion.
You are being browser highjacked. You are already invaded, so it is not going to just remove and will keep re-installing and changing your IE home page and settings. When you get this fixed( later in the game)-run SpyBot with IE tweeks off, when it is fixed, put IE tweeks back on in SB so to keep IE from being highjacked.
You have to find the adware and remove it from your registry and other hiding places. The problem is it re-installs, so if you can't find it all you might have to do a system recovery and then pluck anything left out of your registry. I mean- run your Anti virus or what you use to show the scripts, keyloggers,IE ojbects which might imbedded ( some of these are good)trojans, dialers and etc. If it can't remove it all, see the path it shows and go there ( if you are use to playing in your registry ) and remove bad regis keys ( BACK Up your critical system files first before you remove registry files.VCOM is what I use to help with registry backups etc and if you have admin /owner priviledges on your pc some pcs will let you back up your registry files with out having to go into dos and/or safe mode. You have the bugs already living in your pc, so manually take them out, if you have to and your programs will not, and they have to be cleaned from registry so not to keep re-installing- the path should show you where to find most,( your anti virus web site should help you in seeing how to take these things out- Norton's does) sometimes you have to look further than the actual path it has puled up- like it might say c:\systemfiles\winsud32.exe , which is an adware threat in my pc, so follow the path and remove it. Sometimes things in registry hide( the actual place it is might not be exactly where the path said it was) and it is a cat and mouse game to find them, but presevere. If you are not use to messing in your pc system files, please get some help , if anyone close to you is user friendly with all of it.
Oh, I am researching the best protection to buy as some others on here, Pest Patrol, Spyware Eliminater, and Lavasoft, plus others are checking out different types.
I also put a decent anti keylogger on my pc as seems best to have one now days.
Good luck and I am sure some of these tech types can help you in a more professional way.
I just feel for ya, cuz am just coming out of that trip. I was not using IE , but Netscape as IE was too dangerous in being exploited, but my daughter was surfing with it ( briefly) and boom. I use Mozilla now, and IE is blocked all I can block it. I could not even drag the thing ( IE)out of my pc since I have xp os and it came installed. Good luck.