I have  a windows xp ., and recently switched internet service to att/yahoo and
when trying to download the antivirus protection online(from same internet provider )  I get to the install page.  it jumps to a window where it says: unable to navigate the webpage.  I am conected to the internet, I have checked all connections., and last two TIMES I tried to correct the problem with tech.support , I guess they do not have an idea since they have not been able to help me so FAR. I know I can buy it , but since is free with the PACKAGE .  I did have norton before but I made sure I uninstalled it before trying to install the yahoo SOFTWARE. A better solution:

Anti-Virus
AVG Free
Avast

Choose only one.
Then add the following:

Spybot Search and Destroy

AdAware

AVG Anti-Spyware

CCleaner.

You will now have a WELL rounded protection package that will perform better than most ISP packages without being a hog on System Resources...

Best of all it's all FREE.

But you have to update and run scans regularly for it to be effective.

Good Luck.Thanks Patio., I have installed all what you suggested and everything so far has been well.  thx. Excellent news.
I have found most packages that ISP's offer contain a lot of bloat and unneccessary fluff...
I prefer my tools to do just what they were written to do.

Remember to update and scan regularly and you should have no issues at all...