Whats the name of the trojan, if you know you have one, it must have a name?

As for AV and Spyware stuff.

Avast.com for the AV program. Use this alongside Immunet which is a cloud based AV & Spyware tool. Both work together very well. You can use Spybot and Malwarebytes to scan for Spyware, but don't use the realtime scanners they want to install. The above mentioned programs will catch the alerts and all you will be doing is slowing the machine down.

You can also do something called Sandboxing. Basically, this runs your internet explorer in an isolated environment so anything that happens within it, won't affect the rest of your computer. When you clsoe IE, anything naughty that may have happened is deleted and your system is safe. A free one you can use is sandboxie (http://www.sandboxie.com/). Its easy to setup and should prevent further issues.

Cheers

Matt