Does a single router within network block virus?

[goutom]

We have two network (one have internet access and other doesnt have) within a same office and some pcs are connected to both the network using two NIC. So i am planning to implement a router in between those network and as it implement default routing so we can share all the resources. So does this network design help me to make both the network secure from virus as one of the network should be worm free. What i personally think that implementing a router will reduce worm replication. So please guide me whether or not to go with the design.

 

[Emerald]

the short answer is NO

 

[sturm]

Routers will only help prevent attacks from the outside by masking internal IP addresses, unless you have ports open and/or ports forwarded.
Anti-virus is needed to stop a virus.