New build problem: os won't boot

[rewertz]

I just finished a new build and installed the motherboard drivers and vista, but whenever I turn it on it seems to get to the gigabyte logo page and just stops there without continuing on to boot vista. I flashed the bios b/c both dvd drives weren't recognized and it seemed to solve that problem, but vista still won't seem to boot after the flash. After flashing, I made sure that the boot sequence is such that it boots from the hd first. Any ideas why this is happening?

Gigabyte ma790gp-ud4h, phenom x2 940, sapphire 4870 1 gb, zalman 9700, gskil 2gbx2, 2 pioneer dvd burners, corsair 650w, antec p182.

 

[rewertz]

I removed the logo and on the post page it gets as far as identifying the cpu, then lists a memory check and says 'okay' and then lists memory information and says, 'ddr2 800 unganged mode', and hangs up there. Normally, after listing the memory information, it would move on and list all the ide devices, etc. Any idea why it's hanging up after listing the memory info? Is there a memory problem? I have 4 gb installed and under the memory check it's identifying the 4 gbs.

Thanks for your help.

 

[rewertz]

Here's what I found by snooping through the bios: the 2x2gb gskil modules were detected, but under the 'auto' settings it was listing their speed as ddr2 800 instead of 1066 and they were receiving 1.92 volts instead of the 2.0-2.1 volts listed in the gskil product specs. I changed the speed and increased the voltage by 0.1 volts. I shut down and rebooted and it seems to have worked.

Is this a common problem? Why did the auto settings list the modules as 800 instead of 1066 and underpower them?