No monitor. And not a souped up system. Let’s assume the power supply is rated for 300 Watts. And if I used the panel with a 12 volt deep charge battery?
There’s no simple answer. There are panels of many sizes.
If you want to do this you’d be better off with a laptop. They’re engineered for low power consumption and designed to run off DC. The DC/AC converter after a solar panel is costly and reduces efficiency. And they make very low power computers for use with solar panels in undeveloped countries.