Running with no software firewall isn't a good idea. You can turn Win firewall on (providing you're not using any other software firewall) & allow FW through the firewall.

If UPnP is enabled in your router, you can try ticking the 'Use UPnP' box within FW's tools > options > advanced > firewall. Click Apply > ok to save the change.
Some routers aren't reliable in UPnP mode so in that case you could look at port forwarding.

Did you first of all set up a static IP address & then set up port forwarding within your router's config?
If we had your system details then we'd know your router brand & model & could give you port forwarding instructions specific to your router.

I'm sure that you saw this amongst all the stickies & forum rules: System details - help us to help you -> Provide these details when you post!!!

Could you please post back with answers to those questions?