Panda is running a Windows 7 special. Users can get a 1 year license of Panda Internet Security 2010 for free for 24 hours:
Although it lists many things to fill out, I got to the “confirmation page” by only entering my e-mail address. This is the confirmation page:
Take note of what it says at the bottom: it may take up to 1-3 business days to receive your activation code.
You can download Panda Internet Security 2010 from here.