Linda,

In extreme cases such as yours, there is not a lot one can do other than try to save the personal data that you have by burning it to a CD/DVD and starting with a fresh reformat and reinstallation of your operating system.

Sometimes you can remove your harddrive and slave it to another computer and run the cleaners from that computer to the slaved drive only to remove the bad guys.

Another way is to try to manually remove the bad files from your system...this requires some expert navigational and registry editing and still maynot work as these bad guys have a way to constantly hide and regenerate themselves.

One other way is to try an online scanner like "housecall" from trendmicro or "pcpitstop" but I doubt that it will work as this thing you have has successfully blocked downloading programs to remove it and more than likely have those blocked as well.

The final option is to take it to a qualified repair shop and pay someone to do the clean-up for you.....be careful though as some of these places like "BestBuy" will charge you an arm and leg and only reformat your drive without even trying to save anything.