my computer turned into a zombie tonight.I have a zonealarm pro firewall up and a cable modem hook up. On a windows 98 machine.I had to reset almost every internet setting,and every setting for my firewall.My shutdown screen says YOU HAVE BEEN HACKED!

My norton anti-virus said no backdoors,trojans, or viruses
My registry monitor said there had been no modifiacatons to the registry.
My application monitor said nothing had been changed or modified..

My question is how did someone hack through my firewall without using backdoor programs,and viruses or trojans to gain access..they simply were able to bypass the firewall and get total control.