You're going to need HijackThis http://www.spychecker.com/program/hijackthis.html
run it and look through the log, delete anything that has ads234 in the name. If you're not sure about something, DON'T delete it. Do a Google search for anything you're not sure about. Some items that look bad are really things you need.
You may need to reboot after removal, then run HJ again and see if it still shows up. Sometimes it takes 2 or 3 removals&reboots to get rid of a hijacker.
Once you've cleaned everything out [you should also run Adaware SE, get it at link below] install Spyware Blaster and SpywareGuard http://majorgeeks.com/downloads31.html
Trash IE except for Windows updates, use Firefox, Mozilla, or Opera, they'er not susceptible to hijacking.
I just did all this for my cousin a few days ago. Hijackers aren't removed with regular spyware detectors, the only tool that will work, short of a reinstall, is Hijackthis.

You'll probably have to install Firefox, or another non-IE browser to be able to get some of the other tools.
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