Written 6 Sep 2026. This is a how-to, not a product card.

When the old PC won't boot

No fans, black screen, or stuck on the logo. Check power, the monitor, a hard power cycle, then try the installer USB before you buy a new board.

Soft-off or a quiet ping check only? That is is the computer still on?. House blinked and the working box needs recovery? That is after the power comes back. Haven't flashed a stick yet? Start with make a boot USB for the install. Need the one-time boot keys? See boot the old PC from the USB stick. Marketplace disk still full of old Windows? Wipe it before you install. Ready for the weekend install? Your first weekend.

Skip until you have wall power nearby

If you are away from the outlet and a known-good cable, wait. Don't order a motherboard from one black screen on the couch. Don't dig through Secure Boot menus before a stick has a chance to boot.

What this is

A Marketplace or retired office PC can look dead: no fans, a black screen, or a logo that never leaves. Often the wall cable is loose, the monitor is on the wrong input, or a soft hang needs a hard cycle. An installer USB that reaches a menu means the board is not dead — the disk or OS is the problem. This note is the calm check before you spend money.

Step 1: wall power

Confirm the outlet works (a lamp is enough). On a desktop, find the rear PSU rocker and set it to on. Seat the power cable at the wall and at the computer. On a laptop, check the charger light and try a known-good brick if you have one.

Step 2: the monitor

Seat the video cable at both ends. Pick the correct input on the screen (HDMI or DisplayPort). If fans spin but the picture stays blank, try another cable or another screen before you blame the board.

Step 3: power button once

Press the power button once. Listen for fans or beeps. Watch for any logo. One press. Then wait a few seconds.

Step 4: hard cycle

Hold the power button about 10 seconds until everything goes dark. Unplug wall power. If the laptop battery comes out, remove it. Wait 30 seconds. Plug power back in (and the battery if you removed it). Press power once.

Step 5: try the installer USB

If you already have a stick from make a boot USB, plug it in and open the one-time boot menu: boot the old PC from the USB stick. Prefer the UEFI USB entry when you see both. If the installer menu appears, the board is not dead — treat it as a disk or OS problem. Marketplace wipe during that install: wipe a Marketplace PC before you install.

Step 6 (optional): reseat one RAM stick

Only if you are comfortable opening a desktop and it is not under a sealed warranty you care about. Power off. Unplug wall power. Open the case. Pull one module, then push it back until both clips click. Leave sealed laptops alone tonight.

Step 7: stop for tonight

Do not buy a motherboard or a PSU tonight after one black screen. Write down any beep pattern if you heard one — it is a later clue, not a shopping list. Sleep on it. Come back with a known-good stick and a second screen if you still need them.

What this is not

This is not a soft-sleep awake check (is the computer still on?). It is not Wake-on-LAN troubleshooting (when Wake-on-LAN won't wake the computer). It is not house-wide blink recovery for a working box (after the power comes back). It is not a reason to buy a new mini PC tonight.

What next

Need to write the stick? Make a boot USB for the install. Stick ready, need the boot keys? Boot the old PC from the USB stick. Installer up and you want the weekend path? Your first weekend. Still choosing Debian vs Ubuntu Server? What OS to put on it. Soft-off only? Is the computer still on?.

Optional: note that the old PC failed to boot (and whether the USB installer came up) in Lab plan — username + passkey, no email. Skip if you just want to keep reading.

Skip

• Skip buying a new PSU or motherboard tonight after one black screen.
• Skip opening the case if it is under warranty and you are not ready.
• Skip Secure Boot rabbit holes before the stick boots.
• Skip opening SSH to the internet.
• Skip this if fans and SSH are fine and you only need an awake check. Use is the computer still on?.
• Skip this if the house blinked and the working box needs recovery. Use after the power comes back.