It seems your router is doing NAT (network address translation). This means your router has one WAN IP, learned using DHCP (for example 172.16.12.34), and a complete internal network. For the internal network you configured the IPs 192.168.0.100-192.168.0.110. When your computer sends a packet into the WAN, then the router will forward the packet and replace the sender address with its own WAN address. The receiver of the packet will not see that the packet comes from your computer, he will see a packet from the router and think he talks to the router. If the receiver sends an answer, then the router will look into the NAT table, see that this answer packet is for your computer and forward the packet to you. This works fine for outgoing connections, because the router will find the packet destination in its NAT table. For incoming connections the router will not find the connection in the NAT table and discard the incoming packet because he does not know where to forward the packet.
Regarding your observation that you cannot access the file shares on your computer anymore: access to the file share is - from router perspective - an incoming connection. As stated above this does not work.
Regarding your observation that your computer does not get an IP if you disabled DHCP on your router: when DHCP was enabled on your router, you got an IP from your router and this IP was for the internal network. If you disabled DHCP on the router, then the router does not give you an IP address anymore. You don't get an IP address from your WAN because this is blocked by the NAT on the router. The router knows that WAN and internal network are different networks, so he must block DHCP.
This is not a firewall issue, it does not help to switch off the firewall in the router. What you will need to do is one of the following options:
- Configure the router so that your computer is an exposed host. This means that the router will forward any packets without a matching NAT table entry to the exposed host.
- Configure the router so that he does port forwarding. This is like exposed host, but not for all ports, only for the necessary ports. This is more secure than exposed host.
- Configure the router not to do NAT but to act in bridge mode/bridging mode. In bridging mode the router will just act like a HUB or switch and not do DHCP, NAT, filtering and other magic.
- As historystamp said you can put all computers in your room behind your router. In this case your room will have full access in your own network, but computers in the WAN can not access your local network.
And last but not least: if you have so little network knowledge, then please consider asking your local admin before adding routers to the network. When you are doing it wrong and your routers DHCP server is connected to the WAN, then you will break IP on the WAN.