Motherboard problem?
 

Got my hands on a few spare parts from my cousin and decided to slightly upgrade my old rig. It run with no problem, but as I left for lunch it was frozen when I returned (as in, stuck with the screen, nothing moving). Did a force-reboot and nothing loaded, no BIOS, no video input to the monitor at all, nothing. Not even beeps from the motherboard were heard. Anyone can think of a diagnosys, and a probably solution?

I have to say that what I did change was the Power Source, added a slave IDE and changed the motherboard as I had an ECS motherboard (basically a no-name) before and got a Gigabyte one from my cousin.

Here is a vid of the PC "starting" if it may help you:

I'd start by disconnecting everything....pull the battery and jumper the "clear everything on thr mobo" jumper. Once done connect nothing other than the power supply, keyboard and monitor attached to onboard video if possible and reseat all ram. See if it boots. If it doesn't then swap for a different power supply if possible and try again. If you can get it to boot then slowly add components.

Yeah tried everything from reseating-ram to changing the CMOS. Still nothing. In the end decided to put the power-source on my old pc so I can still use it if this one doesn't. In the end, both pcs behaved the same so the power source seemed to be the fault and changed it. Works fine now.

Glad to hear it. Game on!