System not triggering?! Any help?!!

[Blacklightbulb]

Today I've put together a new system for a friend. The problem is, it isn't triggering aka it doesn't reach bootstrap / BIOS!

When I turn it on:
The fans are working even on the Gfx Card.
The DVD Drive is working and so is the HDD.
There is however no beep signals from the bell.
The system just hangs, fans turning, no output whatsoever, not even video signal.

Was hoping you'd give me some advice!

Details:
System:
Athlon 64 x2 7850
M3a 770 ASUS AM+ MOBO
2 x Corsair 2 GB 800 mhz ram
Gainward Nvidia 9800gt 1024MB
580W PSU

Other details:
PSU works fine checked and is powerful enough too.
Gfx Card checked works on other systems.
RAM checked on different systems and made sure its in the right DIMM slots.
CPU ?? no way of check that
MOBO ?? no way of checking that either
I reseted the CMOS/BIOS properly by battery and jumper, following the manual more than once.
I checked each jumper on the MOBO to be on the right place.
I took the MOBO out of the case and tried it with one good stick of RAM, CPU and Gfx and still nothing.

At this point I'm thionking it's either the processor or the motherboard, no?
Please any suggestions or help for a fellow member and my fellow mate here, about to experience UBUNTU 64-bit?

EDIT:

Are you guys serious? It's not the first time I've build a system and not the first time to encounter trouble. Sure I've connected everything, and everything I connected is connected properly and securely. I've spent the last five hours checking that everything is perfect. The RAM is not the problem. It works on other systems. It's supported and for now there is only one stick installed in the appropriate DIMM slot.
Now that I realize this thread is probably useless. I mean what else can I do, besides test the processor and the motherboard!

[Tipped OuT]

Basics first.

Is your display hooked up properly?

[damis648]

You're right, it is probably either motherboard or processor. I know that once before I forgot to connect the 4-pin CPU power connector and the same thing happened to me. Did you make sure to do that?

[CharlesA]

My guess is that the mobo is fried. I had a similar thing happen on a new build. Got a new mobo and it worked like a charm.

EDIT: I assume everything is hooked up correctly, power etc.

EDIT2: I've used both ubuntu 9.04 x64 desktop and server (with desktop installed..) with no problems outside of the normal hiccups with video drives, but those are easy fixes.

[NoaHall]

Check your RAM. Try remove one module at a time, motherboards can be weird about where they are.

[Xbehave]

Sure I've connected everything, and everything I connected is connected properly and securely. I've spent the last five hours checking that everything is perfect.
remove everything. check with just PSU,CPU,RAM
still fails? well as your PSU&RAM are checked, then check your CPU in a second machine (if possilbe),
this will most likely be fine meaning the problem is a broken mobo,
if it fails then you know the CPU is broken but should check the mobo with a 2nd processor as they may both be screwed.

One more thing have you checked the motherboard jumpers and the battery. We are not calling you stupid but a lot of the time stuff doesn't work for simple reasons.

[Blacklightbulb]

remove everything. check with just PSU,CPU,RAM
still fails? well as your PSU&RAM are checked, then check your CPU in a second machine (if possilbe),
this will most likely be fine meaning the problem is a broken mobo,
if it fails then you know the CPU is broken but should check the mobo with a 2nd processor as they may both be screwed.

One more thing have you checked the motherboard jumpers and the battery. We are not calling you stupid but a lot of the time stuff doesn't work for simple reasons.

Yes, everything is checked, I'm taking the components back to the store my mate bought them from for testing and replacement. It's probably the motherboard. Thanks anyways!