I am new to Linux and have Ubuntu on a computer. I booted my computer up and went into my network settings and changed it from Static IP to DHCP assigned. I rebooted. When I rebooted my monitor stopped working as soon as Ubuntu started to load. Then I noticed that my monitor was giving me a "out of range" error message through it's blink codes. So I swapped out for a better monitor and it worked again. It had somehow changed resolution from it's normal 800x600 to 1650x1280. I tried to go to the Desktop settings and change it but it ONLY showed 1650x1280 at 60hz as my only options. So I went into Terminal and launched Grep disabled IPV6 which I needed to do because my internet on it was slow. I rebooted and voila it was back to my 800x600 again.

Why would messing with my network settings mess up my display settings?

As to why it is changing your resolution. I am clueless. However, if you just want to change your resolution, type:
at a console, and it will guide you through the rest of the process. It will also reconfigure other parts of your computer.

Hope this helps!