Where do I start? 1

[brummytezza]

The PC seemed to close down normally but did not switch off nor would the power button close it down. It sounded like the hard drive was cycling.

On reconnecting power the PC powered up without pressing the power button - but does not boot up, nor will it shut down. The hard drive does not operate - but will if the ribbon cable is removed.

Where do I start?

Many thanks

 

[Kamui079]

wow that sounds like a mess.. first thing i'd do is gotto the bios and select "fail safe settings" or the equivelant.

 

[gus669]

Clear CMOS, reset BIOS to default.
Swap out ribbon cable or put hard drive on secondary channel and test it that way.

PC powering up when you plugged in the cord is nothing new and shouldn't be worried about. But if your not shutting down properly and then not powering up using the power switch properly then replace the switch, or using a screwdriver short the 2 pins where the switch leads are attached to the mobo. This will tell you if its the switch.

Possible bad PSU would hurt to swap that out.

Unforutnately it seems you may have a bad mobo if this doesn't work.