Sorry, I'm new to Raspberry Pi and ALL of this. I figured out how to customize config.txt for my screen, either directly from the card in the boot folder, or using SSH at "sudo nano /boot/config.txt". I added the following lines under the [all] subheader...

hdmi_cvt=1024 600 60 3
hdmi_group=2
hdmi_mode=87
hdmi_drive=2
hdmi_force_mode=1

I also uncommented (removed the # from the beginning) hdmi_force_hotplug=1.

Everything else I left at defaults.

Now to figure out why the system is so unstable. I'm wondering if the "sudo apt update/upgrade" as recommended the Chris's Basement youtube video may have messed things up, so I'm trying again without it. Other possibilities include the screen's power supply not providing enough power for everything, or the touch interface gumming up the works,

The problem was indeed "sudo apt update/upgrade". Everything worked fine without any package upgrades, but I wanted to make sure I could get upgrades. Turns out that using the FULL upgrade command "sudo apt full-upgrade" worked fine, and all is stable. Apparently full-upgrade preserves dependencies and removes unnecessary packages that are no longer needed.

This n00b is learning! Thanks for bearing with me! :-)

I keep running into this problem because I keep forgetting how I fix it.

In my case, uncommenting this line in /boot/config.txt addresses it for my 1024x600 screen:

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
disable_overscan=1

This post brought to you in honor of DenverCoder9.