I feel the need to, once again, commend you for getting your husband to "cease and desist", from using file sharing sites and P2P networks. It's a major step!
You wrote, "Now that we are working from a clean slate I would like to uninstall the free 90 day trial of Norton and use AVG and other free security, but I want to make sure that I'm downloading the proper tools"
The first order of business: "I would like to uninstall the free 90 day trial of Norton".
The only indication I have, as to which operating system you're using, is in your "mini-update" post, where you wrote, "I think Vista has compatibility problems (can't wait for Windows 7)". I'm going to presume ... Vista it is! As to which trial version you have installed, I can't even venture a guess. (NAV '08? '09??) Nor do I know if it really matters, as long as it's only their A/V you have installed.
First know. I'm not familiar with Norton products, no less the trial versions. If my information is in any way "off", I would welcome any corrections! That said, I would first go to Start>Control Panel. Double-click on the "Programs and Features" icon. Look for anything related to Norton, Symantec, or perhaps Live Update. If the trial version IS listed there, click on the program and then click on Uninstall/Change and follow the prompts. Reboot. Once done, I would suggest running the "Norton Removal Tool". Choose the appropriate product on the list, as the steps may differ depending on the product you have. Even if the trial version is listed in "Programs and Features", I would still use the tool to pick up any remnants.
It may be over-kill, but if you run into a problem, you can also try using the Revo Uninstaller ( http://www.revouninstaller.com/ ) . It's free. Have no fear.. it's a "good free". Unlike some of your "hubby's" PREVIOUS "free" choices. In a prior post, I suggested using (and keeping) CCleaner. The "slim version" can be download from here. And the set up instructions here.
The second order of business: '..installing AVG and other free security'
One of the reasons I shy away from recommending software, is because what works well for one person, may not work well for another. Many factors come into play. I can only recommend (some of) what has worked for me, and perhaps others. I can't assure you they will work well together, keeping in mind the difference in systems, but I can assure they are all safe to use.
Netty, you mentioned installing AVG. Some people love it. Some feel it's becoming bloated and are likening it to McAfee and Norton. I can't speak for it. Why not try it? If you like it and it doesn't pose a problem for you, keep it. If you find it problematic, I would recommend either Avira's AntiVir Personal - Free Antivirus or avast! Home Edition.
I would also suggest Javacool's SpywareBlaster. It's a "prevention software that protects against ActiveX based Malware installation. It also protects against known tracking cookies being installed in Internet Explorer, Mozilla Firefox and adds thousands of known Malware installing sites to the Restricted sites zone of Internet Explorer". This tutorial should be of help, if you choose to install it. If you don't already have an additional browser (besides IE7 or IE8) you might want to consider another, such as Mozilla's Firefox.
I have both Malwarebytes' Anti-Malware and SUPERAntiSpyware FREE Edition installed, which I use as stand-alone scanners. Again, only my opinion, but I would suggest installing at least one of them.
End of business! Closing chapter of the book! And perhaps, my longest post to date!
Netty, the above is by no means a "total security package". It may sound trite to say "in the end it's your choice", but it happens to be true. Another reason, I rarely (if ever) post what I have above, is because it's only one persons opinion. Try using the forum's search function to get an idea what other people think. You already made a great deal of headway, having your husband abandon LimeWire. Let's hope he sticks to it. If not.. at least you know you have an "alternative solution".