Keyboard & mouse "dead" on power up

[Pazuzu]

I have a Dell 5100 which is approximately 2 years old. When I switch on the mains supply there is usually a brief activation ( sounds like hard disk or fans ) & when I subsequently press the button on the front of the case the system starts up. At the moment this is not happening. There is no light showing on the keyboard, the red light that shines out from the base of the mouse does not appear. The power light shows amber on the monitor and pressing the button furthest left results in message "In power save mode, press any key on keyboard or move mouse".
So far I have tried removing all connections & powering up. I have also checked for loose boards & connections inside the case. Any ideas? Is this most likely to be a hardware problem?

 

[Pazuzu]

Problem resolved !! ?

For reasons beyond my understanding the system booted on the latest attempt. I cannot tell what the problem was - but it has made me wonder if I should try & get some maintenance cover !!

 

[iss]

one of the quirks of Dell machines (and some other brands) is a annoying habit of "locking up" once and a while which gives you just the symptoms you describe. sometimes it comes out of this after several attempts at booting, sometimes only after completely unplugging the system from and power source for 15 min and sometimes only after the system has been stripped of it's components and each component reinstalled after a tedious process of powering up, shutting down, add component, power up, shut down, etc.. etc. until the sytems appears to be trying to boot.