I don't know of any way to troubleshoot the drivers if you can't boot up.
I strongly recommend against Norton. I have never had a good experience with it. When it comes pre-installed on a machine, I remove it.
You can get AVG Free http://www.download.com/AVG-Anti-Virus-Free-Edition/3000-2239_4-10320142.html?tag=mncol&cdlPid=10861654
and Spy-Bot, http://www.download.com/Spybot-Search-Destroy/3000-8022_4-10122137.html
at no cost. If you install these and run your Windows updates regularly, you will greatly reduce your chances of getting a virus or spyware.
You can TRY reinstalling Windows which should leave your files and programs intact. I don't know if it will work, but that's the first thing to try. (You shouldn't need your install code, but Dell should have placed a sticker somewhere on your machine with the OS keycode on it. Sometimes, they're on the back, but usually on the side or bottom of the computer. If you can't find it, we can get software that will find it once you're able to boot. Also, the OS and other original software may be on a partition on the hard drive, but one thing at a time...)
Here's the method:
Boot the computer using the XP disk. Insert the disk. Turn off the machine and turn on with the disk still in place. (Hold the power key down until the machine turns off, then turn back on.) The machine should give you a message saying something like, "to boot from cd, press any key." If you don't get this message, you may have to change your bios settings to boot from cd. (Let me know.)
When you see the "Welcome to Setup" screen, you'll have some options:
To setup Windows XP now, press ENTER
To repair a Windows XP installation using Recovery Console, press R
To quit Setup without installing Windows XP, press F3.
Press ENTER to start the Windows Setup. DO NOT choose "To repair a Windows XP installation using Recovery Console, press R." If you repair using the recovery console, you'll lose data, so DO NOT USE IT.
Accept the License Agreement and Windows will look for existing Windows Installations.
Choose the XP installation you want to repair from the list. (You probably will only have one.) Press R to start the repair. If REPAIR is not one of the options, END setup.
Setup will copy the needed files to your hard drive and reboot. Do not press any key to bott from CD when the message appears this time.
Setup will continue as if it were doing a clean installation, but your applications and settings will remain intact.
Once you are working again, you willl need to run Windows updates. You should run anti-virus and anti-adware programs before updating your Windows. If you think you have a virus and AVG and SpyBot have missed it, let me know and I'll give you some more information.
I hope this is helpful. If not, then post back with your questions/concerns and I'll continue to assist.