Question System turns on when power connected

[NightHawkRMX]

Just put this system together. Some parts are used some are new.

I couldn't find the front panel on the motherboard (it's unlabeled I think), so I didn't plug the power button in.

However, I accidentally flipped the PSU switch and the PC turned on. It turns on every time the switch is flipped on? Why?

I5 3550
Chinese RGB cooler
Dell Optiplex3010 board
2x4gb Hyperx 1600mhz
GTX 960 2gb MSI GAMING
Seagate 750gb HDD
SeaSonic M12ii 520w Bronze
Thermaltake case.

The PC boots to bios fine and all hardware shows up.

 

[Shay Green]

Ok have you got the motherboard manual?

 

[kerberos_20]

check bios setting, usualy there is section with what pc will do once it gets power (stay powered off / power on)

 

[NightHawkRMX]

I have no mobo manual as its an oem board. There is a conector that looks like front panel but is unlabeled. Ill try the connectors.

Ill check bios. I didnt think about that.

 

[NightHawkRMX]

Wait when i turn it on it says power button cable failure. So maybe it sees this and boots automatically

 

[Shay Green]

I think it detects no power button is connected

 

[NightHawkRMX]

Nope i connected the switch and the switch works, however It still boots with power on.

No bios setting i see