As a router isn't "installed", either as hardware or as software in a computer, you won't find any reference to it.
Make sure that both your PC and your laptop are in the same "Workgroup".
Set at least one folder in each PC as "shared" by right clicking and selecting the Sharing & Security option.
Any firewall software needs to be configured to allow access to the networked computers, which may involve adding their IP addresses in a "trusted" section.
You should then be able to access the shared folders in the remote computer by going into "My Network Places".