I am in the middle of a computer nightmare. My old machine was semi-stable and a random freeze could not be resolved with a new system install. I decided to replace the video card, mobo, processor and ram. My hard drive is only a few months old and the problem had been showing up before it was installed. Processor is a P4 3.0/800 MOBO is a ECS L4VXA2 Hard Drive is a 160GB/7200 Seagate CD ROM is a Benq Power Supply is a Vantech Stealth RAM is Kingston PC2700 333 Graphics is NVidea FX5500 VGA I can't get any video signal or POST info. I have tried running the machine with just the CPU and RAM. There is a very odd problem. The Hard Drive or CD-ROM will power up if there is no IDE cable connected. If I plug an IDE cable in neither will power up. I have tried using only the cd-rom or only the hard drive, jumper settings and a different IDE cable. Same problem. The IDE cable is keyed, so I know it is not in backwards. I have also tried both IDE mobo connections. I have tried clearing the CMOS both by jumper and by removing the battery. I have both power connectors connected to the MOBO. I am using a USB mouse and it is not lighting up. I am wondering if this could possibly be a PS issue - except the PS worked fine in my other system and the CPU fan does power on and spin. I am wondering if the slots (VGA, USB, etc..) on the board are getting power. There are only two jumpers on this board - the CEMOS clear and the bus speed select. I have tried the bus speed in both positions and no luck. The CMOS just stops me from being able to turn the thing on. Also, I have another video card (same card but PCI) and I can't get that to work either. I don't have any of the case lights coming on. I keep checking for shorts and even tried my old mobo and am having the same problem (so I figure it's not a jumper or short issue). The one thing worth mentioning is that I have one of those Windows wireless keyboards. It connects via PS2, but I was wondering if no keyboard could stop me from seeing POST data? I have an extra USB mouse that I am connecting via a USB -> PS2 adapter. I don't think the keyboard would be causing the power issue with the drives, so I may have two problems here. Any/all help would be appreciated. I can't get ANYTHING to display on the screen.