Hello, any insight is highly appreciated. I bought a high end graphics card for my HP Media Center PC, and then a generic 450w power supply, having no money to buy a REAL PSU, but the vendor said it wouldn't fail me (don't you just love it when they do that). Days after installing it, it died on me, of course, and for a couple of hours I feared it had taken everything else with it. After checking for burn marks and stuff like that, I reinstalled the orginal 300w PSU and, what a relief!, everything was fine, nothing had burned. So I saved some money, did some light research and finally settled on the Antec True Power Trio 550w. Well, cutting to the chase. It wouldn't power up my PC. It won't, actually. Nothing happens, and I do mean Nothing. No POST, no beep codes, no fans spinning... zero. Tried 3 times and 3 times I had to go back to the 300w piece just to check on not having damaged anything and to start and continue what has been a pretty futile search for answers. The TP3 works. I tested it on an old machine and everything was peachy. I contacted Antec Support and they said they had no idea what it could be. Of course, if it's not broken, they have no obligation to help me fix it. The only bit of wisdom they offered was that their PSUs would sometimes not work on HP-Dell-Gateway-Emachines and others... How nice! The product is supposed to be "universal" and "backwards compatible" and such and such... but it may not work with most computers. HP has not replied. And I've heard from some people that my MoBo might be protecting itself from the amount of energy... ¿?... Is that for real? I tested the PSU on a very old MoBo, having to use it in 20 pin mode, and everything came to life. Why wouldn't it work for a newer, two hdd bearing, pci-express, "entertainment enhanced" CPU and machine? Really, how is this possible? and is there some way around it, is what I want to know. Some tweaking that can solve the incompatibility issue. Something other than a new MoBo or a new PSU. Any thoughts? The motherboard is an ECS RC410-M.