Can't get xp to start due to virus

I got some virus yesterday and now I can't get past the "windows is starting" screen.
It freezes at the same point when booting in safe mode.
After seeing I was infected I ran spy bot and remove what it found. Ran Ad-aware and remove what it found and ran counter spy and remove what it found.
System still infected with something. Opening windows with stuff like, you are infected do you want to install xxx software to remove, gambling sites, porn sites and others. Counter spy kept blocking stuff from loading in start up and regestries. The system finally locked up and I powered it down.
Now it will not go past the blue "windows is loading" screen.
I did a repair install with the windows cd. Still stops at the same place.
I am stuck. How can I try to fix if I can get into windows at all?
I would prefer not to format the C drive and reload.
Any help would be great thanks
Ted

 

You could try booting your computer using the Last Known Good Configuration

 

I did also try booting using last know configuration. And it still froze at the windows is starting screen.