Summary: After a RAM upgrade, my computer goes into an endless reboot loop every time I turn the computer off and back on again, or restart. It posts fine, gives me the mobo's splash screen, freezes, then reboots. If I completely unplug the computer and cut the power to the PSU, and then turn it all back on again, it boots just fine, sees the RAM, and proceeds normally. I can leave it on all day or use it heavily with no problem. But the next time I restart the machine, it will go right back to the endless reboot cycle and I have to cold boot the system again to make it stop. Details: The motherboard is a Gigabytle GA-EP45T-UDP. The RAM is 8GB of Patriot Viper Series (up from 4) PC3-10666, 2GBx4.All timings on each stick are exactly the same, 7-7-7-20. I have not OCed this machine in any way. All settings are stock. Things I have tried: - I have taken everything out of the computer except CPU+heatsink, RAM, and video card. Made sure everything is secure. - I took all the RAM out except for one stick, and tried that stick in different DIMMs. - Tried a different stick. - Reseated the motherboard. - Tried a different output on my video card (no idea what that might do, but I thought I'd try it) - Cleared the CMOS - Reseated all the power/reset/led cables. - Checked EVERYWHERE for something that might be shorting the board...all cables that aren't connected to anything are bundled together with zip-ties and carefully set to the side. None of the contacts are touching the case or any part of the motherboard. I'm stumped. I can't find anything wrong. This computer used to boot every time just fine with the 2x2GB sticks. But even if I set it up exactly the way it was before, it still goes into this endless cycle. This problem did not occur until I upgraded the RAM, but I have no idea what doing that triggered to cause this. Could it be coincidence? Any ideas? The one thing I have not done with this board is update the BIOS. I don't like updating BIOS versions unless I'm absolutely sure that's what's causing the problem. But I'm not super experienced with "tweaker" boards like this. Any insight would be appreciated. Machine specs: Motherboard: Gigabytle GA-EP45T-UDP CPU: Intel Core 2 Quad Q9400 2.66Ghz (no OC) RAM: 4x2GB Patriot PC-10666 Video Card: ATI Radeon HD 4850 (only using one display right now) Sound Card: Creative X-Fi PCI-E Storage: 2x Western Digital Caviar internal SATA drives (RAIDed) 1TB each. Optical Drives: 1 LG Blu-ray/HD DVD player/burner, and 1 LG DVD-R w/lightscribe ...I can't imagine that any of the peripherals would be relavent, but I have a Razer mouse, a Saitek keyboard, a Seagate external backup drive, a Canon scan and printer also connected to the computer. The problem occurs even when all but the keyboard are disconnected, though. Ideas appreciated. I'm getting tired of having to cold boot this thing every time I want to use it! EDIT: Okay, just to be absolutely clear: this problem occurs even WITHOUT the hard drives attached. Therefore, it is NOT a Windows issue. The computer freezes on the BIOS spash screen. I cannot boot into the BIOS, much less to a CD--as soon as I see a picture, the computer halts. I do not have the opportunity to mash DEL to get into setup or F8 to get into Windows startup options. It's literally Power on, POST beep, BIOS splash, HALT, reboot, rinse, repeat. So I know for absolute certain 1. This is NOT a problem with my hard drives. 2. This is NOT a problem with my OS. The problem exists in total absence of OS and hard drive. ...that leaves, I believe, the BIOS, the PSU, the RAM, the video card, or the board itself.