Possible virus affecting network connections, etc?

Question

My iBook (running 10.3.9) just started doing some bizarre things. The network connection has slowed down considerably, and 2 of the 4 e-mail accounts that I have set up in mail no longer connect (and I know it's not those accounts that are acting up, though it's always the same accounts on the same server). I've experienced this problem using wireless and ethernet on one router and ethernet on another, both of them using entirely different ISPs. Other computers hooked up to those routers connect fine.
Also - and this part is a little more bizarre - some websites refuse to come up. So I can go to google, but I can't go to versiontracker or the apple store (just as an example - there are far more sites that I can't go to). Sometimes when I close the browser and reopen it I am able go to a particular site that I couldn't before, but always about half of the sites that I try to go to won't come up. When I try to update my software (for example, the auto-update for Office) it tells me that it can't make the network connection.
I then decided to try to look at what programs were running, and the forcequit menu shows nothing unusual. I tried to open activity monitor to see what was running in the background, but it was unresponsive (I'd click and it wouldn't open). I then decided to try using diskutility, but it did the same thing as activity monitor (wouldn't open up). Other utility applications seem to open fine, however I opened net info, and when I looked at the usage of my ethernet connection it reported no traffic even when I was successfully loading a webpage (I've never used net info before, I so I don't know if that's what it's supposed to show).
I was unable to download Norton through my university the first time because it couldn't make the connection. I rebooted and it was able to download it, but when I installed it and tried to open Norton is said that file was missing or damaged and couldn't be opened. I deleted it and reinstalled (from the same installer) and it didn't work again. I then deleted the download, downloaded it again, and it opens fine. I was able to get the new virus definitions, but it took what I perceive as longer than normal to download them. I then started scanning my harddrive, and it crashed when it was about 10% done with the scan (that is, the screen froze and the gray lettering superimposed on top of the screen said I needed to restart my computer). I restarted my computer and ran it again - same result. I then started going from folder to folder and was able to get the documents folder but it crashed midway through the applications folder. I then went through application by application in the applications folder, and the only thing that it crashed while scanning was the keynote application. I rebooted, scanned keynote again, and again it crashed. I then trashed keynote from within Norton, but when I went to empty the trash it said I didn't have permission to trash certain files (which didn't show up in the trash bin, but I think were part of the keynote package contents). I had read-write permission for keynote, so I was a little confused by that. Anyway, I rebooted and started my folder by folder scanning again. I was able to scan the library folder, but it crashed in the System folder.
Soooo... that's when I decided to seek help, because I really don't want to have to go through folder by folder to figure out what programs are infected or causing the problems (and I don't really know if the fact that they crash Norton means that they're infected and I should delete them, or if it means something different entirely). Any suggestions?

Answer 1

Please let me suggest that you re-think Norton. I've read many, many posts in various forums here to the effect that Norton causes far more problems than it fixes (and some that say it fixes nothing at all while wreaking all sorts of havoc).
Search for Norton and you'll see what I mean.
I do see a number of posts saying ClamXav (I won't swear to the spelling) is quite good as a replacement . . . if you want one.
Glad your problem is fixed -- hope Norton doesn't make another!