I know very little about computers, so apologies if I describe something incorrectly. My PC was working normally yesterday, but after moving it back to my family's house, it will no longer boot. I checked that the cables were connected as they were before.
When I press the power button, the lights briefly come on and it makes its usual startup sound, but then it shuts off. A moment later, it tries again, repeating the same cycle endlessly. I've had this happen before, and unplugging the power cable for a few seconds usually fixed it, but that no longer works.
The computer was wrapped in bubble wrap and handled carefully during the move. The two lights on the front, including a blue-red flashing LED, both come on briefly during each attempted startup. What should I check first?
4 Answers
Disconnect the power cable, hold the computer’s power button down for around 30–60 seconds, then reconnect the cable and try again. This can discharge leftover power and sometimes clears a startup loop. If you have a dedicated graphics card, make sure the monitor is connected to its video output rather than the motherboard’s port, and test with only one monitor.
Try a different wall outlet, preferably in another room on a different circuit, and test with another compatible power cable if you have one. Also disconnect everything nonessential, such as extra USB devices, and try starting with only one monitor and a keyboard connected.
A mechanical hard drive could potentially be damaged during transport, but the fact that the PC powers off and repeatedly restarts usually points to a power, memory, graphics-card, or motherboard issue that should be checked first. Avoid repeatedly forcing it to start until you’ve inspected the connections and diagnostic indicators.
Open the case and look for diagnostic LEDs on the motherboard. The labels may indicate a problem with the CPU, memory, graphics card, or boot device; the motherboard manual should explain what each light or flashing pattern means. If there are no diagnostic lights, try reseating the RAM and graphics card, since a connection can become loose when a computer is moved.

The two front lights both flash briefly during each startup attempt, then turn off when the computer shuts down. I’ll test another outlet and cable.