PC Start-up failure – how to diagnose and fix


These are just some of the issues to look at before Windows starts – not exhaustive but based on experience – hope these are helpful to you.

No power, no sound, nothing on screen

  • Most common is that the PC isn’t plugged in as a cable is loose.
  • Check the fuse – usually the quickest way, rather than changing the fuse, is to use the power cable from your printer/monitor (or Xbox 360) as many use the same (kettle) lead.
  • Try using a different wall outlet
  • Power button faulty – many PC’s there is a micro switch beneath the plastic power button –  the plastic that holds this in place can sometimes break – does the power button feel spongy? It’s possible to pull off the front bezel and re-seat the switch – you may be able to pull the microswitch out of it’s housing and get the PC working. If the switch itself is faulty you can use a small screwdriver to carefuly touch the front panel pins (on the motherboard) which will start the PC.
  • Static build up – hold power button in for 5 seconds. Disconnect all leads from PC. Leave for 10 minutes – try restarting PC.
  • Motherboard failure
  • Power supply failure
  • USB ports faulty/damaged – very common but often mistaken for a power supply/motherboard fault. Damaged USB ports can cause a short circuit.

Power, lights on PC but nothing on screen

  • Check the lead from the PC to the monitor. Has the PC recently been moved or serviced? Often the cable is plugged in the wrong socket. Sometimes a PC has 2 possible options. One socket is attached to the motherboard – usually located higher on the back of the PC. The other lower down and is horizontal.
  • Is there a light on the monitor?  If you have another PC/laptop try plugging this in.
  • If you can hear PC fans and hard drive – or can hear the Windows startup sound you may have a faulty monitor – check the power and monitor lead.
  • Motherboard failure  – remove the side of the case and carefully check for leaking/bulging capacitors – see below electrolyte leaking – extreme example. The PC was still working intermittently

caps leaking dell sx270

  • RAM failure – sometimes system will beep if it detects RAM defect or RAM has become loose. Has the PC been moved recently? In most cases, you can remove side panel of desktop PC and carefully re-seat the RAM **  – refer to manufacturers instruction book or Google.

Computer turns on but beeping

  • Always caused by hardware problems. Sometimes relatively easy to fix as above RAM issue – you can try re-seating graphics and any other add-on cards.  .
  • There are listings of beep codes available at http://en.wikipedia.org/wiki/Power-on_self-test not exhastive and you have to listen carefuly!  

Other common messages before Windows starts

  • Flashing cursor top left of screen – possible hard drive failure. Remove any DVDs from optical drive and any external hard drives/USB dongles.
  • Non system disk or disk error – as above
  • NTLDR is missing or corrupt – can be hard drive failure or Windows system files have become corrupted – latter can be fixed by replacing system file.

** Please observe static precautions. Leave PC plugged in and touch metal chassis or wear an anti-static wrist strap. If in doubt, call a professional.