Cannot map network drive after switch from Verizon DSL to FiOS

[jg123]

We just switched to Verizon FiOS today after several years with DSL. 
Speed is 20/5.

They installed the Actiontec MI-424 router.
I had them run coax to the router for TV and cat5e for Internet connection.
Later I intend to try to use a Linksys router as a subnetwork, but for now am just using the Actiontec.

We have one PC and one laptop, both running XP SP3.  The laptop is a Dell 620, the PC is a Dell Dimension 2400.

Both can access the Internet fine.  The laptop is connected wirelessly just for now, the PC is hard wired to the router.  I intend to use the laptop hardwired also, after I run another cat5e cable.  I could plug it into the router for seeing if that works.  But the wireless access should work also.

I made a new profile on the laptop for wireless access to the router.

Any suggestions?  I'm a networking newbie so please be specific.