What tools have you run to remove them?
Have you tried Adaware or Spybot Search and Destroy?
Google for them - they are free and very good.
Go offline and disable other anti-virus and spyware programmes when you run them.
Run them one at a time - and close them down when they've completed their scan.
Does this help?
Are you dial up or broadband?
If you are dial up - go to your internet connections folder -
you'll find it in the control panel - and right click on your internet connection icon.
Look at the properties - and make sure the number it is dialling is the one for your ISP - that nothing has changed it without your knowledge.
There is also a ultility called 'Hijack This' which will scan your registry for threats -
but it's really for the techy types I think.
I found it easier to back up my work, internet settings etc to disk -
(not forgetting your e-mail address book and web favourites - DOH!)
and reformating completely.
Just do a clean install of Windows and you've got a fresh start.