Newly built PC does not start up, someone please help

[Kam]

I have built a PC with the following configeration and it does not start up, only the fans and the Optical drive starts, there's no BIOS either as the screen stay's blank with "no signal detected".

Before I installed the parts, I checked that they are all compatible, according to the Motherboard specs and Gigabyte tech support. Here is what I have installed.

-Gigabyte GA-81955X Royal, Intel 955X S775 PCI-E ATX ALR
-Intel Pentium D Processor 920, LGA775, 2.80 GHz 2x2 L2 Cache
-Crucial 2 x 1GB. 240PIN 128MX64 DDR2 PC2-5300, Unbuffered
-Sapphire Radion X1600XT 256MB PCIE
-Hitachi Deskstar 7K250 SATA1 150GB Hard Drive

I checked with gigabyte tech support about compatability of these parts along with the motherboard specs. Does anyone know why the system does not start up?

Before I installed this new spec. including MB, I was using the same case and PSU with another MB and other parts and it was working fine.

I checked the installation and as far as i'm aware, I connected everything properly.

I would like to know what is causing this problem, from previous experience, I think the Motherboard may be faulty or it could be the memory modules, not sure.

Can someone please help.

 

[kirock]

First check your video card and monitor connection. Reseat the video card and make sure you've installed the 4pin molex power connector to it (if req'd), this maybe at the base of the card on the mobo itself.

Check and recheck that the mobo is not grounding itself on the case. Did it come with insulting washer for the mounting screws? Use them!

A common problem of the fans spinning but the PC does not turn-on, is the 5V "power good" signal is not present at the mobo. This is on the 20 pin PSU to mobo connector (sometimes 24pin now). It's pin 8 and usually grey colored wire. This can be caused by a bad PSU or a short on the mobo (defective) or a short of the mobo to case and therefore ground. Reattach this to ensure it's seated properly.

In general check all your PSU connections to HDD, mobo, video card, the case power switch.

Cheers.

 

[Kam]

Thanks, I will do all the things you've mentioned and see if it works.

 

[Kam]

I took the motherboard out of the case and just connected the CPU, 1 Memory, Graphics Card, reset the CMOS and I ended up getting the BIOS screen.

When I screwed the MB back into the case with the above components, and screws on 4 corners of the MB and 1 in the middle, just the fans spin and the BIOS does not start. When I take the screw off from the top right and bottom right corners of the MB, I get the display and it goes into BIOS.

When before the BIOS screen, the CPU fan spins for a little while, stops, then starts spinning again and I get 1 beep. Is that normal?

What is going on here, am I putting on too many screws on the MB or doing something else incorrectly?

 

[kirock]

OK, see you practically have it fixed. You ARE grounding the mobo. Look around for some tiny paper washers (disc) these are suppose to go bewteen the screw head and the mobo. This prevents the screws from making electrical contact to an active trace on the mobo and shorting it to ground. They should have come with your mobo and may still be in the box.

Be very careful about leaving it on too long if it doesn't POST you could damage the power supply or the mobo. Turn it on, no post, then quickly use the back PSU switch to turn it off.

Cheers.

Edit: 1 beep is good POST.

 

[mailpup]

Just checking. You never mentioned standoffs. Are you using them? You know, metal or plastic "spacers" between the motherboard and the mounting side of the case.

 

[Kam]

Yes, I am using the standoffs and I managed to find few plastic washers that go between the screw head and the mobo. The system now boots to BIOS and I managed to install the Operating system. It’s Strange because I never had to use these before.

I now seem to have another problem as everything is so slow. The mouse arrow has a late reaction whenever I move it, and when I click on something, it takes longer for it to open. It's like another application is taking up most of the memory, the whole system is much slower. Thing is, all the components are new and I'm thinking if it's anything to do with the memory modules or the CPU or because the RAID function has been disabled in CMOS, CMOS error. Any suggestions?

 

[kirock]

You can try to boot to BIOS and set to optimal performance, see if that hepls. Sounds like the CPU is way underclocked. But at least you got it going.
While you're in the BIOS check that the CPU freq is correct for yours.

 

[Kam]

The CPU is a P4 920 2.8GHz Dual Core Processor, the system should set its default values automatically. I'll check the sittings in BIOS for anything unusual, thanks.