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.