No boot

Hello
Switched on the computer this morning and it refuses to boot. I cannot switch it off either using the button at the front of the box. I have to switch it off at the main. The CPU fan switches on and runs and the light on the CDRW is on but the four LED's at the back of the computer are red. These are normally green. I have taken all the PCI cards out and disconnected the CD/DVD/Floppy drives but it still happens. I have even switched the hard drive for a back up with no luck.
Anyone any ideas please?
Many thanks
aw56001

 

Clear the CMOS would be your best bet.

 

Does it POST successfully?

 

Power supply going bad, Is this an eMachine ? eMachines are know for bad power supply's and Switches...

 

Absolutely nothing there when I switched on. No, it is not an emachine.
I have researched how to and cleared CMOS. When I boot up now I get the option to reset or load default BIOS options.
I have reset all my BIOS options and after a few unsuccessful tries Windows loaded successfully. I can restart Windows but however when I shut it down the fans keep running and I can't switch off using the button on the case. If I can't boot up after a shutdown and have to do the CMOS clear again.
I spoke to a friend today who has built many systems and he said that the power controller on the Motherboard has gone and a new MB, processor and RAM will have to be sourced however I can leave the system permanently switched on until he sources, and gives me a date when he can fit the parts.
This is just a courtesy post to say thanks for the advice that you offered.
aw56001