Q:

How to set up a network connection with 2 ISP,s 2 Routers and 1 switch

I want to use 2 ISP providers at the same time, to avoid downtime. Here's a diagram of what I want to do:

What settings should I use for the routers and can I force PCs to use ISP#1 when online and ISP#2 when 1 is down? 

A:

How you do it will depend on the routers you have. What you are trying to do is configure the routers in failover also known as high availability mode.
You can also you two ISPs with a single router and use WAN failover. You also are able to use a dedicated device to do link balancing and connection failover.
First, you need to determine what routers you are using and then I suggest looking for the terms above to find the configuration you need to build. If you have a specific question about how to do something please let me know.

