Processor (CPU): Intel Core i5-7500. This is an old processor, but the performance can still meet your needs and the price is relatively cheap. If budget permits, consider upgrading to a newer processor, such as Intel Core i7-8700.
Motherboard: Choose a motherboard that supports CPU and has enough interfaces and expansion slots.
Memory: At least 8GB DDR4 memory. If your budget permits, consider upgrading to 16GB or higher.
Graphics card: NVIDIA GeForce GTX 1050 or AMD radium RX 560. These graphics cards can provide enough performance to play videos and other live operations.
Storage: At least 256GB solid state drive (SSD) or mechanical hard drive (HDD) for storing operating system, applications and real-time files.
Power supply: Choose a reliable power supply to ensure the stable operation of your computer.
Chassis: Choose a chassis suitable for your motherboard and graphics card to ensure good heat dissipation.
Considering the second-hand options, you can find cheap substitutes for these components in the second-hand market. However, please note that there may be uncertain quality problems with second-hand parts, so please check and test them carefully before buying.
Finally, please note that the unmanned live broadcast needs to meet the requirements and configuration of the live broadcast platform. You may need to check the documentation of the live broadcast platform or contact technical support to determine the best computer configuration and settings.