I have an identical setup to you with the same memory, processor, and motherboard (the X48T-DQ6 is the same as the EX38T-DQ6 except the chipset is validated to run at higher clocks) and experienced similar problems at my first boot.
Of course, make sure that you first clear your CMOS by unplugging your PC then shorting the pins for 5 seconds.
After that, if you get the computer to start and display a boot screen (The Gigabyte logo) then crash, you probably have the same problem that I had. The problem is that the BIOS defaults to 1T timings for 2GB sticks of memory. Go into the BIOS configuration then into the M.I.T. (Motherboard Intelligent Tweaker) options and set the memory timings configuration to MANUAL instead of AUTO. Then go to the command rate setting and change it from AUTO to 2T. The memory is not rated to run at 1T which is the AUTO setting and this causes the computer to crash.
Also make sure that the DDR3 overvoltage is set to +0.40V. The normal setting is 1.5V while this OCZ memory needs to run at its manufacturer specified 1.9V to achieve its rated timings.
After changing those settings it should work.
Also, I have a request for you since you have the same configuration as me. I am having trouble even slightly overclocking the processor even though the configuration is stable at stock speeds. Changing the CPU Clock Host Control to even 334 MHz (1 MHz overclock) causes the computer to refuse to boot. I think that the memory may be the issue as GIGABYTE has no 2GB sticks DDR3-1333 or higher in its validated memory list for these boards. If you experience the same problem, please tell me so that I can confirm my hypothesis. I think that this may be fixed in a future BIOS update, but for now I am just running at stock speeds.
Anyway, I hope this fixes your problem. Let me know of your results.
Intel Core 2 Quad Q9450
2 x 2 GB OCZ DDR3-1600 CL7
2 x Diamond Viper HD-3870 (In Crossfire)
2 x Western Digital 750GB HDD
2 x Samsung SH-S203N DVD-RW
Hiper HPU-680 680W Power Supply
Antec Nine Hundred Case w/ 6 120mm & 1 250mm fan
Xigmatek Red Scorpion HDT-S1283 CPU Heatsink
Or another idea, if you have a flash stick, flash your bios from it, i used it , worked great, plus i liked the idea, if i had a issue, i could put the flash stick into my other computer and get a diffrent bios on it and give it another whirl.
Yep mobo is pretty new but it does not contact the usb at all. The LED on the stick is not powerd on at any moment. I think it's either bad flash or RAM can't have enough power to boot up. Best is to return it and get a new one with the F1 bios version.
Flashing the first bios shouldn't affect the backup. If it posts, the backup may not kick in automatically because it thinks the first bios is working, as it does post. There should be a button that lets you switch to backup manually. I forgot which one, but it should display on POST screen.
I know it is an old thread, but I'll share the solution that I've found on the net. It worked for me. When boot cycle begins, you have to break it. To do this, just cut off the power when it boots, but before it shuts down and reboots again (you have about 5 secs.). I did this with the switch on PSU (try few times). We need to tell the board that the boot was not sucessful, and then it will restore last working configuration. The power cut-off does the trick.
By the way, I've got F1 bios and it works fine. I've flashed it to F2 once (and met infamous 'boot cycle'). F2 bios caused probles with Windows 7 sleep function (boot cycle appeared when system was woken up from S3). So I had to reflash it with my F1 again (thank God I saved it before updating, there is no F1 version on Gigabyte's website).