What made you suspect that Norton Internet Security was responsible for the icon problem? --- And were you able to successfully uninstall Norton completely (some uninstalls go better than others)? What antivirus/firewall/antispyware combination did you replace Norton with?
At this point, I'd say that you first need to make sure there aren't any current malware infections, and then - once clean - repair system files.
Try using the tools and procedures in the 5-Step Security Checklist, whether you determine you need to post a HiJackThis log or not --- http://www.techsupportforum.com/sec...lease-read-before-posting-hijackthis-log.html
--- And check for Rootkits as well --- http://www.pcsupportadvisor.com/rootkits.htm
Also, try a Registry Cleaner to help clear away damaged leftovers from infections. I like CCleaner for this sort of thing: it's free, it's tiny, and it works. Use the Cleaning functions of CCleaner to clear away unnecessary and potentially dangerous temp files (malware often tries to hide in temp files). Use the "Issues" function to help clear up problem entries in the Registry - keep running this function until it reports "no issues found". It can also help uninstall programs. You can download CCleaner from the following link --- http://www.download.com/CCleaner/3000-2144_4-10315544.html
Once the system scans completely clean, try a run of the Windows File Protection program (like an XP version of the System File Checker) --- from the Start/Run box, type in "sfc /scannow" (without the quotes). The program will run in the background, and leave entries in the Event Viewer when it stops & starts - and report it's work there [Start/Control Panel/Performance and Maintenance/Administrative Tools/Event Viewer]. SFC might request your Windows XP CD, or need to be pointed to the location of the Windows installation files (the .cab files) on your hard drive.
Some feel that deleting the ShellIconCache file & allowing Windows XP to re-create it can help restore the right icons to the right programs. ShellIconCache is normally a hidden file (located in your /Windows folder), so you'd have to temporarily set Windows Explorer to be able to view these files. To let Explorer see hidden files, open Explorer, and from the "Tools" menu, select "Folder Options", then "View", and then "Show hidden files and folders" -- and remove the checkmark from "Hide Protected operating system files". Then delete ShellIconCache, and reboot.
Best of luck
. . . Gary