The error message "Reboot and Select Proper Boot Device" indicates that the computer cannot find the boot device that contains the operating system12. This can happen if the hard drive that stores the operating system is damaged or failed, and the BIOS cannot detect it or read from it23. A failed hard drive can also cause other symptoms such as clicking noises, corrupted files, or slow performance4.

VDI is a technology that allows a company to provide desktop environments to third-party developers while still maintaining control over the corporate network. VDI creates virtual desktops on a remote server, and each user gets their own desktop environment that is isolated from the other users. This allows the company to maintain control over the corporate network, as the virtual desktops are not directly connected to the corporate network.

https://intellinetnetwork.eu/pages/what-is-a-poe-injector
The quickest way to resolve the issue is to install a Power over Ethernet (PoE) injector to provide power to the IP phone. An unmanaged switch does not provide PoE, so an injector is needed to power the phone.

Testing the power supply first ensures that the correct voltage is reaching all components, which is a common cause of boot issues. Modifying BIOS settings is not possible without a POST. Checking PCIe cards or replacing the motherboard are secondary steps if the power supply is functional. CompTIA A+ Core 1 objectives cover power supply testing as an essential troubleshooting step in system startup issues.

If a user is unable to connect a laptop to a projector or videoconferencing system and sees the error message
"No source found," the next step should be to check the display settings on the computer and set them to extend/duplicate. This will ensure that the laptop's display is being output to the external device. References:
CompTIA A+ Certification Exam Guide, pg. 514