i'ved had this problem before. i uninstalled it manually by modifying the registry (it's in symantec's website) but ended up reformatting my hd cuz i couldn't even install norton 2003. 2004 was the worst version i'ved ever used.
Intel Core 2 Quad Q9550 2.83Ghz || 4GB OCZ 1066 DDR2 RAM || GIGABYTE GA-EP45-UD3P Motherboard ||
PNY XLR8 GTX 470 || Raptor 300GB 10,000 RPM HDD RAID0 || Windows 7 Professional 64-bit