Alright heres the problem. Last night I was on my computer surfing the web like normal when all of a sudden it froze. Couldn't move the mouse or do alt ctrl del or anything.

So I just turned it off manually. Now come to this mornnig I go to turn it on and it sounds normal like its starting but on the monitor theres nothing. Just a flashing green light. So I fiddle around with it and still the same thing. I then replace my video card same thing, replace the hard drive same thing. I cleaned it out with the dust off spray and still nothing.

I have reset the cmos and unplugged all the power and stuff still black screen. It turns on fans spinning and all that but nothing on the screen. I can't even get into BIOS or anything.

I'm starting to think my PSU is dying like it can't get enough power in the rails to fire up the HDDs or something. If someone can please help me I'll rep you for life. I'm almost about to go waste my money on a PSU so please help me make sure its 99% my PSU.

Heres a list of things I've done:

tried different monitors.
tried different adapters which the monitor plugs into then plugs into my video card
tried different video cards
tried different power supplies
tried different motherboard/cpu
tried a different CPU for my original motherboard
tried different RAM
tried different varations of which hard drive is the master and vise versa
tried booting with out memory
tried booting with just a hard drive and a video card
tried clearing the CMOSS
switched different batteries on the motherboard

Thanks guys and gals.

It seems like you have almost rebuilt a new computer but still using the same case????
are you running to ground somewhere? Try a different case.

is the monitor powered from the computer and draining power or are you powered straight from the wall?

Not much left to try, check board isn't shorting on the case, I have also known the BIOS chip to be corrupt

Yup monitor is plugged into wall not to the computer. I've checked all my electrical and backings that the motherboard sits on. I just don't know. I've pretty much given up.

Hi is it making any beeping noises at all? Beep error codes?

In fault finding of any kind, you have to look for the common factors.

the only common factors throughout all of this are the case and the hard drive. Maybe the hdd is what is causing the power loss. maybe there is a short to the case there. I would try any or all of these options.

1.dismount the hdd so that it is still connected but not attached to the case. cheapest option.
2.try with a different hdd.
3.with a different case

Also, are you using the same power outlet from the wall? Is that giving a full supply? Try a different socket.