I'm building a new PC from scratch. I work in the IT industry, so I'm not a complete novice at such things. My specs are as follows:

Motherboard: Asus P5n72-T Premium
Processor: Intel Core2 Quad Q9450
Memory: G.Skill F2-8500CL5D DDR2-1066 (I have a total of 8GB, however am currently only running one 2GB Dimm for troubleshooting purposes)
Vid Card: PNY NVidia GeForce 9800 GX2 1024MB

I have a single SATA drive installed and a SATA DVD-RW. Everything else I have disconnected from the board for troubleshooting.

The problem that I'm having is the PC will not boot unless I clear the CMOS via the jumper on the motherboard. This includes entering the BIOS and making any changes. Once I save changes and reboot I get no display, no post beep, nothing...

I have Windows Vista Home Premium 64bit installed by just clearing the CMOS everytime I reboot. It appears to run fine while in Windows, however I did experience two lock ups at misc times.

In addition, this is not my first motherboard. The first one did the same thing and I had it replaced for the same model via Newegg. The 2nd board is doing the same exact thing.

On the old board I did update the BIOS to the newest version, also replaced the BIOS battery. This made no change. I have not yet done these things with the new board.

Any ideas? Thanks!

Welcome to the forums!

Is the memory at the right voltage?
Try lowering the speed of the memory to 666 MHZ.
Try alternating the memory stick.
Try a different brand of memory if you can.

The right voltage for your memory should be 2.0-2.1v.

I have tried manually setting the voltage to both 2.0 and 2.1 with the same results. As soon as I exit and save changes, no post, no display, until I clear the cmos once again (which of course kills any settings I have made).

With this board I didn't have any other brands of memory to test, but I did with the previous and had the same results with settings at Auto. I will have a few different types of memory to test with tonight when I can continue troubleshooting.

Just an FYI, with the settings at Auto the voltage monitor in the BIOS states my memory is running at 1.9~1.92v.

Thanks for the help!

Edit: almost forgot, no I have not tried setting the memory to 666 Mhz, but will do so tonight.

I had a little time to troubleshoot a bit more, so here is a bit more info.

I disconnected all of my SATA devices for troubleshooting purposes.

I tried a stick of Samsung memory I borrowed from work and had the same issue.

I performed the disable splash screen only, same results.

I also tried dumbing the memory down to both 666 and 800, still no go.

I did find that I could enter the bios and as long as I didn't save, it would reboot and post properly, though I would get the same CMOS checksum error from the original CMOS clear.

Something else I found that after a failed post, if I moved the stick of RAM to a different slot, it would sometimes boot and give me the previous post failed error, please enter setup and reset defaults. Of course if I do so, I'm back at square one.

Well, I think I've had it with this MB. I know Asus has a great reputation as a MB manufacturer, so I would still like to stick with them. I'm also not currently running SLI, but would like the option in the future.

That being the case, can anyone recommend a board that would be a good fit for my existing hardware?

I'm currently leaning toward the ASUS Striker II Formula LGA 775 NVIDIA nForce 780i SLI ATX Intel Motherboard.

G.Skill has it on their list of tested MB's, so that's a plus.

Thoughts?

You could get a 750i chipset motherboard also, which is a little cheaper.