PC won't boot... no video... what happened...? Help!

Hey guys, having a big problem here.

My girlfriend wanted to upgrade her PC. Previously we upgraded the mobo, CPU, and RAM. It was working great for months. Today we bought a new PSU, GPU, HDD and monitor.

I unplugged everything before getting started, then opened it up. I unplugged all PSU connections and removed it.

Then I removed the HDD cage and put the new HDD in beside the old one, then put the cage back in.

Then I started plugging everything back in - motherboard, DVD, HDDs. I then plugged the GPU in and connected the 6 pin.

At this point everything should be fine. It might not be important, but I forgot to pick up an extra SATA cable so I unplugged the old HDD thinking I would just plug the new one in and install the OS.

So at this point everything is installed and has power cables plugged in.

I then plugged the monitor in, and then plugged the PSU into the wall and flicked the power switch to "on".

Then I tried booting it and nothing. No video.

I noticed by doing a hard shut down, and rebooting, it sometimes would briefely start (fans running) then shut off, then start again. Also, the HDD and DVD seem to be working... Normally though it just starts everything running but no video (without quick reboot. But it does happen sometimes)

To troubleshoot, I tried uninstalling the GPU and plugging the monitor into the onboard video output. I also tried the old monitor. I then unplugged the PSU and put the old one in (no gpu) and it's still doing the same thing. I've also tried plugging the old HDD in, and I tried removing the CMOS battery.

Right now I'm guessing it's got to be a dead motherboard but I just don't know how come!!

Specs: HP desktop
Serial/IDE cable DVD-R
Biostar G41 M7 mATX mobo
Intel E5400 CPU
4 gigs DDR2 800 Kingston value RAM
old 5400rpm 320gb HDD
new Hitachi 7200rpm 1TB HDD
new Corsair 500CX PSU
new HIS 5770 1gb

(old 280W psu)
 
Well my girlfriend figured it out.

I had tried removing 1 stick of RAM and nothing changed... but on her suggestion we swapped the other one and voila, it booted. I then tried putting it back in, no go. At first I figured, ok, dead RAM stick. But then I just swapped the slots and now it's working fine with everything installed!

YAY!

I guess this can be closed. How about first person to say "congrats" gets best answer so MouseMonkey can close it ;)
 

ghnader hsmithot

Distinguished

Was it dead ram or dead ram slot?
 


That's the wierd thing, neither. I guess it must have been either some dust in the slot or it got dislodged (even though I did check it was in there properly). I took out the RAM on the left side (furthest from CPU) and it didn't boot, then put that back and removed the right side stick and it booted. Then I put the stick from the left into the right slot, and it booted, and then I put the "dead" stick in the left slot, and it booted with all 4 gigs showing up. So basically I have no idea what happened, but it's working great now.

The WD Caviar Black HDD is soooo much faster than her old one, she's pretty happy now :)
 

ghnader hsmithot

Distinguished

Even though it could be the ram as you were saying.I doubt it was.If there was ram.The pc should at least boot up.