I have norton 2008,and it

You may have let your updates get turned off and viruses have got in on you.
Norton hasn't been doing that great these days. You have to stay on top of your settings all the time to make sure there set to the highest level and your updates need to be checked regularly also.
You might try booting up in safemode and trying to reinstall from hard drive or repair it and see if this helps. If it lets you repair it go ahead and run a virus scan while in safemode. Although the last Norton I tried to run in safemode wouldn't work. You might try to repair it before you try safemode.
Go to the control panel and add & remove programs and click uninstall norton. It should give you the option to repair it. If it does run repair and see if it helps. If it does run updates immediately and then run a full system scan. Go into the settings and make sure you are set to the highest level of protection in Norton options and settings. I always set mine to repair and then delete if repair failed.
good luck.