Disconnect from the Internet to isolate your system
Try to completely deinstall Norton Internet Security 2004 via Norton own deinstall utilty..to do this you may need to run the install or even reinstall Norton to get a clean deinstall
Get your Norton Internet Security 2004 cd and start the install to see if it looks for previous version or ask if you want to repair or deinstall...reinstall and then deinstall if you need too but get Norton out and then get your system stabilized after (reboot (cold it can't hurt)several times, check for issues ... but if your system is stabilized you should come up the same on each boot with no new issues
Now get back online and go to http://www.trendmicro.com/en/home/us/personal.htm first and run Housecall to check for virus (bet you will not have any but you will have spyware
Then go to http://www.microsoft.com/athome/security/downloads/default.mspx ...this page has links to most places you want to go to get what you need (you can also go to www.download.com for these)
Get and run all three anti spyware Lavasoft Ad-aware,No charge,Spybot Search & Destroy (S&D),No charge Microsoft Windows AntiSpyware (Beta)No charge(be sure there up to date) and clean out any spyware
Then get Windows Update and Office Update ...
Finally you ready to reinstall a antivirus I personally like Trend Micro PC-cillin and its $25 for the year via the Microsoft link (also in stores most antivirus will have rebates to the point of being fee if you have previous version of other antivirus
That my preference but I had customers that have had good luck with Norton and the other antivirus
Tophat from 1980 on: building, installing, repairing,& troubleshooting computer systems from Mainframes and minis to pc and servers from little LAN to massive global WAN in all flavor of protocols,ATM,Frame,IP, x25, etc.