The serial number will be a 4 digit number. Go to Help->About and you can find it there. It's also going to be on the daughtercard. That's the smaller card that is attached to the PCI 7200 card.
How is your machine set up? Is it still set up for the laser, or does it have a router attached? Post some pictures of the machine, the inside of the control box, and the inside of the PC.
As far as downloading the router setup from WinCNC's site, it's just a screen. It won't change the way your machine is set up. The machine has to be wired for the router and the wincnc.ini file and the macros all have to be set up to work with it.
Is this a servo machine? Is it an XYZ machine, or just XY? Some laser machines don't have a Z axis, I can't say about the SS machines.
If it's already mechanically set up with the router, is the router wired? Can you turn it on and make the router run?
What is the four digit serial number?
Does the machine operate at all with WinCNC?
These are some of the things you're going to have to know before anyone can help you... except Shop Sabre..., they built it.