Computer taking 15-20seconds to start up

[bendoon]

In the morning after my PC has been off for a couple of hours the computer will take 15-20seconds to start up after the power button has been pressed... This is happening every morning now. The PC also the other day would not start at all for 3 hours until I plugged out the 16pin power connector and re-inserted it into the mainboard. Any ideas why this is happening? Power supply is a "Corsair Professional Gold Series 750AXUK". Case is a HAF X. THanks

 

[clutchc]

My first thought would be a failing PSU, possibly capacitor related. Even high-end PSUs can fail. But of course, that doesn't rule out a MB issue either.

 

[smeezekitty]

That sounds like a failing PSU. I had an old PC with an AT supply that failed like that.

The fan in the PSU failed but I didn't know it and kept operating it for hours on end.
It initially took a second to turn on after you switched it on and then that time got longer and longer and longer until it took 15+ minutes to start up.