Hi Tibor,
When you think that Windows XP Home has inbuilt antivirus, you are probably thinking of the inbuilt firewall.
Totally different to antivirus, but just as essential if you are running cable or ADSL. Hackers don't bother as much with exposed PCs via 56k dialup when there are so many exposed PCs via high speed cable and ADSL.
Activate your firewall.
I've been in IT since 1986, and have sold & installed Nortons Antivirus 2003 on 20 PCs recently - all for different clients, all installed OK with no problems.
I've also worked with corporate antivirus gateways - my last fulltime job had me maintaining antivirus gateways for 10,000 Macs and PCs, and another company with 5,000 PCs, as well as any others ( IT Security Analyst hat, stopping viruses and patching 1500 servers against holes in NT or Win2k )
Nortons is good, and works well.
When XP Home failed to install on your PC, and had to be manually completed, it leads me to think that your hardware is not 100% happy with XP ( or XP is not 100% happy with your hardware ! ) XP has got lots of smart routines and drivers and installs on just about anything ( well, almost ).
What brand and model of CD-R do you have ? - the exact model number off the internal casing would be good to know.
You already own NAV 2002, so why not try installing it again, rather than ditching it. If it was the OEM version that came with PC or some other software, it'll give you 3 months of updates, then it'll cost you about $45 for another 12 months updates every year.
Try the free software if you like, but TANSTAAFL.
If you need support, ask me, I'll help you for $0 ( and a coffee or two ! ). I work from St. Ives and am often out around the Guildford area
rgds,
Richard