If you are having a problem starting your computer, try the following:
1. Remove any UPS/AVR and connect it directly to an outlet.
2. Change the Power cable, ensure that the cables are firmly in place on the PSU
3. If possible, try the PSU on another known, working computer
If the computer still fails to start, please submit a ticket.
If the problem is intermittent, i.e. sometimes it powers on sometimes it doesn't,
1. Determine if you leave your PC on a standby voltage, meaning, the power source is not removed through the use of a hard switch (UPS/AVR) or removal of power cable.
2. Find out of the issue occurs when you do leave a standby voltage on the system.
3. Submit a ticket with the above information.