Diagnose a PC That Beeps but Shows Nothing on Screen

A POST that completes with a single beep is a working machine with a broken display path. Checking the cable, the input and the port costs nothing.

Get-CimInstance Win32_VideoController | Select-Object Name,Status,CurrentHorizontalResolution
Get-PnpDevice -Class Display,Monitor | Select-Object FriendlyName,Status,Problem
# try another cable, another input, and the board's own video output

One short beep, three long beeps or a repeating pattern each mean something different per vendor. The pattern plus the board model is the lookup key.

Get-CimInstance Win32_BaseBoard | Select-Object Manufacturer,Product,Version
Get-CimInstance Win32_BIOS | Select-Object Manufacturer,SMBIOSBIOSVersion,ReleaseDate
# note: e.g. 1 long + 2 short, or continuous short beeps

The board needs a CPU, one RAM stick and power. Every removed device eliminates a candidate, and a machine that POSTs in this state names the removed part.

# power off, unplug, discharge
# remove: GPU (use onboard), all but one RAM stick, drives, USB devices, add-in cards
# reseat the remaining RAM in slot A2 or DIMM 1
Get-CimInstance Win32_PhysicalMemory | Select-Object BankLabel,DeviceLocator,Capacity,Speed

A single bad stick or a dead slot stops POST before the screen. Moving the same stick to another slot separates the two.

Get-CimInstance Win32_PhysicalMemoryArray | Select-Object MemoryDevices,MaxCapacityEx
Get-CimInstance Win32_PhysicalMemory | Select-Object DeviceLocator,PartNumber,SerialNumber
# repeat: same stick in slot 2, then a second known-good stick

A weak power supply starts the fans and fails before video. Clearing the firmware settings with the jumper or the battery removes a bad memory profile from the equation.

Get-CimInstance Win32_BIOS | Select-Object SMBIOSBIOSVersion,ReleaseDate
Get-CimInstance Win32_ComputerSystem | Select-Object Manufacturer,Model,PowerSupplyState
# clear CMOS per the manual, then boot with defaults

One change per test, one observation per test. A machine that shows the firmware screen in the minimal state boots, and the last removed part is the suspect.

Get-WinEvent -FilterHashtable @{LogName='System';Id=41,6008,1001} -MaxEvents 5 -ErrorAction SilentlyContinue | Select-Object TimeCreated,Id,Message
Get-CimInstance Win32_OperatingSystem | Select-Object LastBootUpTime
Get-CimInstance Win32_PhysicalMemory | Select-Object Capacity,Speed,Manufacturer