Hi Carlana,
I've got whatever programs came with my new laptop (a windows security suite including
Defender, Firewall, and
Norton/Symantec - the latter of which I had to disable because it doesn't jive well with Windows Mail).
The Windows Defender software is available as a
free download here. It's great for spyware, which alot of the free antivirus programs *don't* have complete protection for. (if you go for one of the free ones, be sure to grab this too.)
Google also
has a free spyware detector, but it's bundled with a bunch of unrelated 'stuff' in the Google Pack - just check the boxes for the programs you do want and ignore the rest. (I think the Microsoft freebie is better, but some of the Google Pack programs are cool for other reasons. Like Star Office and the Google toolbar.)
As to the paid antivirus programs I'd suggest using the following reviews from
PC World and
Top Ten Reviews. They go into detail about what each of the paid programs offers, and how they compare to eachother. Here's
another good article from PC World.
I hope this helps a bit!