Go through the following points until the problem is resolved:

1. Check the power button is switched on.
2. Check for any power indicators on your computer and monitor – are there any lights on?
3. External power. Check the power socket – is it turned on and working? Check another socket that you know is working to see if this makes any difference. If you’re using a multi-way extension plug, try connecting directly into the wall socket.
4. Cables (1). Follow the power cable from the plug socket to the computer and to the monitor. Are all the connections secure? – feel the connections and push them in to make sure they are tightly secured.
5. Cables (2). If your plug socket is working, and all the cable sections are tightly secured, you could have a problem with the connecting cable. Replace the cable with a cable that you know works.
6. Can you hear any noises coming from the computer? If you can, this will indicate that the computer has power to it.
7. Check the monitor, its power cable and its video cable (the cable connecting it to the computer).
8. Some monitors also have a secondary switch to cut the power completely – check if yours has one, and if it’s turned on.
9. Check the monitor isn’t in standby mode.
10. Can you smell anything? If you can smell a strong smell of burning, disconnect all power at the mains immediately, and find your nearest service centre. 

If you have checked all of the above and your computer is still not responding, then you could have a problem with your computer. This could be for a number of reasons, and you will need to get the problem checked out professionally.

For more help with power issues/ problems starting up your PC, see our how-to video How to solve power problems with your PC