We have two networks in our office. Some computers need to connect to both networks at the same time. So I have added a route in the registry and it works. The problem is that one computer can connect to all servers in both networks, but another computer can not access to some servers.

Please advice how can I correctly connect my computers to the two networks.

How are the two networks connected to each other. Do you have routers in each network?

The easiest method is if both networks are able to see each other through routers. This way, you will not have to assign fixed secondary IP address configurations to your computers with static routes.

The easier method would be to have the two networks physically isolated from each other except through routers. You do not want DHCP servers from multiple networks on the same physical infrastructure unless they are isolated by VLAN's.

Each PC can be assigned only one gateway address. If you are using the more difficult method of multiple addresses for the same computer, then you will need to add static routes on the computer using the ROUTE ADD command. Remember to make them Persistent routes.

With this method, you would add a primary fixed IP address and gateway for your PC. Then you would add a secondary IP address to the same network card. Then you would add the route to the PC.

Example:
If the PC address is 192.168.1.50, subnet 255.255.255.0, gateway 192.168.1.1 and the second network is 192.168.2.0/24 then you might add a route as follows:
ROUTE ADD -P 192.168.2.0 MASK 255.255.255.0 192.168.1.1

And for the other network, it would be:
ROUTE ADD -P 192.168.1.0 MASK 255.255.255.0 192.168.2.1

The other way to see each other and connect you computer at the same time. If you have a router, you just need to set the computer name of your computer. Be sure that the work group are the same.

Do you know how to create work group, you just need to do this, go to control panel then, choose network and internet connection. Set up the small office, then follow the statement there, you need to create a work group. Both computer have the same work group, share the folder.

The work is only a trial and error,if you cannot connect in the first time you need to do at second time.