you may struggle to do any of this if, as you've said its damaged\stopping your broadband connection. If you have access to another PC with internet access download Stinger by McAfee, from the following URL:
http://vil.nai.com/vil/stinger/
this is a standalone Virus program and checks\cleans all the latest virus' from your PC, hopefully it will remove the Trojan. Once your systems back up and you can connect to the internet update your Norton Anti-Virus software using the LiveUpdate program and then run this. Hopefully at this point your PC should be clean of virus'. Now you need to use AdAware and Spybot, (ensuring both have the latest updates installed), these together should remove any spyware.
On the downside, depending on the Virus, it may be impossible to fully remove/repair your PC and in such a situation all you can do is format the hard-drive and start again. Ive had to do this in the past when a virus has damaged the MBR, (Master Boot Record), of the hard disk, basically the part of the drive that stores critical system\startup information.
Most virus' work by infecting a host and then running routines to automatically send themselves back out to the internet using just your broadband connection and a table containing popular IP addresses. Theirs a good chance at the moment your PC is infecting other peoples PCs, its a vicious cycle. The best way to avoid this kind of thing is to use a firewall \ virus software \ spyware protection and avoid IE, Firefox in my book is a good alternative at the moment. Hope this helps.