Ditto K.N,
Norton programs are *extremely* resource hungry (actually I’m convinced that’s what’s causing you this grief). I remember once my FS2000 frame rate dropped from 20 to 1.5 while Norton was busy “crash-guarding” my computer – it’s all rather unnecessary, if you have the incorrect setup it will crash anyway!
Do yourself a favour and get rid of anything Norton. I’ve grown a dislike for all Norton products because of their constant meddling with my computer. If you want a nice, little and smart antivirus program, just get hold “PC-Cillin Anti-virus”. One of the best rated Firewall’s is “Sygate Personal Firewall” (free for personal use). Both of these are unbeatable and simple to use.
Actually I can't recall if ME has this feature but if you ctr+alt+del and wait for the task manager to come up, try clicking on the "processes tab" and try to find out which particular application is using up all the resources - I'm not sure if you can do this in ME though, but worth a try. If you continue to experience the problem make sure the Norton Antivirus program is up to date, you may need to download the latest pattern files (normally through the program itself) since this virus has only been around a while.