|There is nothing you can do in a command prompt that will change the fact you can't have two gateway entries. System will only use one.|
You can change the metric on the gateway. This means you put a higher metric on the gateway you don't want to use as a default.
You change this under tcp/ip properties.
" i'm experiencing difficult in remote PC using VNC and can't connect to the files that are in the network! "
This is not right. If you have two pcs networked they do not need a gateway entry on either to communicate via RDP/VNC or network access between them. A gateway is where tcp/ip shoves everything it can't resolve locally.
So what do you mean access a remote pc on your lan?
What is your ip and what is its ip?
In VNC are you using the host name or the ip address to connect with?