So, do I really need virus protection if I have a router?
In short, if you have a PC (running Windows)… Yes…
A router/Firewall will protect you from network based traffic, but Viruses are application based… Think of it this way (and how I explain so people remember 
)…
If you lock the door to your house, does it stop your kids seeing ‘inappropriate’ stuff on Cable TV?
I’m in 100 percent agreement with Grockle. Also, make sure you keep your windows unit updated with the regular security updates from Microsoft. Keep your anti-virus software updated as well. Scan your windows unit on a regular basis for viruses. Try not to open attachments in your e-mail program (attachments can sometimes have an executable virus payload).
It is a good practice to have some kind of spyware scanner on your computer. There are several you can choose from:
You know how in some businesses and organizations they have an internal telephone system?
So you dial their phone number and get a receptionist, and that receptionist can connect you to any of the extensions in the building.
Any of the extensions in the building can usually dial out to the “real world” by bypassing the receptionist.
Well, think of your router as that receptionist. It makes it really easy for those computers ‘behind’ the router to connect to the outside world, while only really needing one phone number (IP address). On the other hand, it’s hard for those in the outside world to reach your computer directly, unless you make the connection first.
This has absolutely nothing to do with the actual conversations that you have, though. It doesn’t block you from visiting websites that automatically install crap on your computer, since you’ll be visiting them, bypassing the router.
it takes less time to install an anti-virus than it does to reformat a computer.
a couple of good free ones i’ve used in the past were AVG and Avast. i found norton to be a resource hog.
it’s also wise to install a spyware scanner like hitest suggested.
I prefer my ‘potential filth’ on TV analogy! 
I look forward to “filth” on TV! 
BAHAHAHAHAHAHAHAHAHAHAHAHA! I love it!
Thanks so much for the answers… though, I’m not sure the iron hymen site was much help 
Both the “lock on the door” and the “receptionist” analogies were good.