We can not recommend these programs more. We have seen far too many computers with Norton on them, fully updated, loaded down with viri. Same goes for McAfee, TrendMicro and others. We have never seen a computer running either of these, updated, with virus infections. You can buy even more secure versions from both of these companies as well.
DO NOT RUN MORE THAN ONE VIRUS PROTECTION PROGRAM ON YOUR COMPUTER!
This can make matters worse, not more secure. Pick one and use that one, and that one only, otherwise you can have conflicts between them.
Malwarebytes' Anti-Malware - Also very good piece of software. Highly recommended. Again, free for home use, and you can buy a lifetime subscription for fairly cheap for realtime protection.
CCleaner - Good Temp File Cleaner to help you free up drive space.
OpenOffice - This is basically a free version of Microsoft Office. It likely does anything you will ever need from Office without the hefty price tag.
Firefox - Internet browser by Mozilla, far better than Internet Explorer. Not only is it more secure, but it is endlessly customizable.
Thunderbird - Powerful e-mail application, also by Mozilla, and again, secure and with lots of add-ons to customize your version as much as you want.
Paint.NET - Like OpenOffice, this is a free alternative to Photoshop. It is not as complex, but it has many of the most useful features found in Photoshop and uses far less resources.
Dropbox - Another file sharing utility, it allows you free storage space to allow other people access to various files. Use our link to get us a referral.
John's Background Switcher - Cool utility that allows you to switch your desktop background in a variety of ways.
VLC Player - Easily the best overall video player you can get for free. Will play pretty much any format.
WinAmp - Great music player, without using a ton of resources.
Picasa - Photo organization software by Google. Richly featured and easy to use.