[Iclipse]

Hi, after recently upgrasing the motherboard, ram and cpu on my pc and having it work fine for a day, i am now very confused as when I try to boot my pc, it will whir etc as though it is booting but keyboard/mouse leds and my screen do not come on. I was told by a friend to check the coloured LEDs on the mobo to see if there was anything wrong. Having looked, LEDs number 1 and 2 are green, 3 is yellow and 4 is red.
My motherboard is a gigabyte p55m-ud2, RAM is corsair 1600mhz ddr3 and the cpu is an intel i5 750, thanks.

[zyper95]

Check all the connections starting from the Power supply, cables, RAM, and video card make sure they are firmly attach. Also, what is the wattage of your power supply? How much RAM do you have? What is your video card? Make sure you are using a power supply that can support all the hardware installed on your computer.

[Iclipse]

As far as I can tell everything is firmly attached in terms of connections, I have 4Gb of corsair DDR3 1600mhz ram, an XFX 8800 ultra graphics card and an OCZ 600W power supply

[zyper95]

How many hard drive do you have? It may be your hardwares are not getting enough power from the PSU. If you have a spare video card try it, to eliminate motherboard problems. If you will be able to boot to POST with another video card then your motherboard is not the problem, it is possible that problem is the video card or you have to upgrade the PSU.

[Iclipse]

I only have 1 hard drive, i'll try out your suggestions when i get home.