Added linksys befsr41 router: have internet but no lan

I had 3 computers & a dsl modem plugged into a 4 port hub. all computers could see the internet & each other.

Decided to add the Linksys befsr41 router cause I'd run out of ports on the hub.

I now have the modem plugged into the router, the router & the 3 computers plugged into the hub.
all computers have access to the net but none can see the other.
so I have internet but no lan.

Hoping its something simple like address?

with the hub I just plugged everything in & it worked.

Also the net seems noticibly slower since I plugged the modem into the router instead of the hub.

This morning everything is working.

Maybe it just needs a looooooong time to recognize the new router.