Next time you can't reach Altavista, try to ping the IP I gave you earlier.
If you can ping it, then you can make an entry in your hosts file to make www.altavista.com go to that IP. Since that IP is one of Altavista.coms many servers, it should work.
You'd want to add this to your hosts file:
I can't really think of what the root of the problem is. It could be your ISP and your Computer has nothing to do with it. The only way to find out would be to use another computer at your house and see if you can get to altavista from it. If you only have one computer and it is connected to a router, try using a Knoppix LiveCD and see if you can get to Altavista. The LiveCD won't change your computer's configuration, and it will run a Linux OS that won't be affected by Norton or anything else your computer might have because it is run entirely off of the CD. If you still can't reach Altavista using the LiveCD, then it is 99% an ISP problem (it can't be a software problem on your computer because you've ruled that out) and you should try calling or visiting them about it. Good luck.
Hmmm... the tracert and ping results are normal, which means that packets are reaching her machine. So.... where are they going? Carla, the next time you can't access altavista, I want you to try the tracert again because what you saw might be tracert results from when it was working. Also, I want you to carefully check if there are any custom rules in Norton that specifically block altavista.com. Another thing is, can you attach a friend's laptop or something to your internet connection and see if you can access the sites from there. If you can't it's definitely an ISP problem and you need to call them.