PC switches off and on

[vikit]

When you switch our pc on it starts to come on, shows the packard bell logo and then switches itself off, then comes back on and then off and it will only stop when you unplug it.

If we press F12 a menu comes up and it stays on, but we have no idea what it means.

The cable is not faulty. Has anyone got any idea what it could be. I have to get some work from it urgently.

Thank you

 

[Tmagic650]

The power supply is most likely going bad

 

[morawski64]

Going out on a limb, but perhaps there is some sort of error in post that causes the system to reboot unexpectedly? I'm not sure, but odds are, you got into the BIOS or Boot Menu, and the fact that you could tells me that it posted correctly, try unplugging your hard drive and remove any disks and see if it will halt on a "no boot device" error. Perhaps there is something in your HDD that when the OS first tries to load, it creates a serious error and reboots the system. Working off of Tmagic's idea, during this boot loop process, do you notice any strange or unusual smells coming from the computer? I doubt if it was a serious power problem, it would last long after being turned on, but who knows. If your computer uses an ATX power supply and it's reputable enough, it should report to the motherboard that it is damaged and it wouldn't do anything at all, except maybe flash the power light.