Motherboard, power supply or something else?

[bigbee]

My husbands computer is a pain in MY *censored*!


Computer fans (all that are connected) run fine.
light on back of computer comes on when plugged in
NO beep sounds when power button is pushed
No keyboard light (num lock) tried pushing it each time I tried something else.
monitor goes into sleep mode after it says no signal.
I have tried to plug in the monitor into the video card and the reg slot
on the mother board (neither worked)

we havent installed any extra ram.

HP Pavilion Media Center m8530f Desktop PC
Hard drive
750 GB SATA 3G (3.0 Gb/sec)
7200 rpm
16X DVD(+/-)R/RW 12X RAM (+/-)R DL LightScribe SATA drive
Memory
Component Attributes
Memory Installed 5 GB
Maximum allowed 8 GB (4 x 2 GB) (64-bit OS)

4 GB* (2 x 2 GB) (32-bit OS)

*Actual available memory may be less
Speed supported PC2-6400 MB/sec
Type 240 pin, DDR2 SDRAM


The monitor works fine. tried it on mine, same with the keyboard and graphics card.
2 weeks ago changed video card, updated everthing and all worked well.

The only thing i can think of is that maybe the mother board is bad or
maybe its the power supply. I first thought of the power supply but after my trip to best buy they made me feel like an idot for thinking that.


Any help would be great thanks!

[Computer_Commando]

...2 weeks ago changed video card, updated everthing and all worked well...

Pull the card and plug monitor into the onboard video.  BIOS should recognize video card is gone and switch back to onboard video.

[bigbee]

I have tried that allready and still the same thing happens

[Geek-9pm]

Memory stick failure is possible.
In a few cases a bad stick can prevent the system from starting. And not even a warning beep. But I do not know if that would apply to your motherboard. Yet it is a quick test. Remove all the memory, power on and and the system should give you some beeps.
http://www.computerhope.com/beep.htm
The fact that you get a beep means that something is working!