Trojan problem

Basically I keep getting these IE popups when browsing using Firefox and something is consuming vast amount of CPU power. Norton also keeps saying that the same trojan is attacking the http port repeatedly as well.
I've run Norton Antivirus, AdAware and Spyware S&D (twice, and got a registry error the second time). Can anyone recommend anyway to deal with this?

Are you able to find out the name of the virus/trojan/spyware/whatever it is? It would be easier to help you if you're able to.

Found the name. It's Trojan Vundo and if google is correct, it's the cause of the spyware.

Ask and you shall receive.

I hope this helps!