Doesn't sound good bro. If the mobo turns on and fans spin with or without RAM, your next step is to try another CPU. If it's a no go, your motherboard is probably done for.
I made a custom harness because the harness that came with the PWR-023 Mp3Car DSATX 220 Watt Automotive Power Supply has 20 pin atx to 20 pin atx Male to Male. My ASUS AT5IONT-I motherboard accepts 24 pin Male ATX Connector. I bought a ATX 20 pin to 24 pin adaptor and plugged that into the harness that came with the PWR--023 power supply and my computer worked fine. I bought ATX connectors and terminals and soldered on the ends and wired it exactly as the harness that came with my power supply with the adapter on. After finished I took a continuity check and checked it to make sure each connection was right and that harness was. I custom length my case fans. 2 of 3 fans were wired correctly, the third had the 12V+ and rotation wire switched. I fixed that. In order to use my custom harness on a home computer power supply,which has a 20 pin ATX Male connector, I would need a 20 pin female to 20 pin female atx adapter. I bought two of the 20 pin to 24 pin adapters and pulled out the wires for the 24 pin connector part and put on the other 20 pin connector. I connected them wrong. they are supposed to be left to right switched, but I wired it parallel and connected my computer, and nothing turned on. Nothing sparked or anything, but when I corrected the wiring and bootup my computer, the hard drive light doesn't flash and the computer doesn't boot.
I used a usb hard drive reader on another computer and the hard drive reads. When I plug in the power to the motherboard, the led light illuminates and when I turn on the power button, the fans spin. When I connect HDMI to my TV from the motherboard, my TV detects something is there, but no image because the computer is not booting. I took out the ram and it makes no difference with or without ram on the display, but I'm not sure how far along the booting sequence goes before the HDMI displays picture. Ever so often the hard drive light flashes for a partial of a second, but nothing boots. My + and - for my power button were reversed and same for hard drive led, when corrected, same thing happens. This does this with the new harness I made and with the one that came with the power PWR-023 power supply with 20 pin - 24 pin adapter.
Anyone know what could be causing my bootup. The hard drive is brand new and as soon as I loaded all my software and went to windows update, everything worked fine even after reboots prior to my rewiring of the harness so I don't have any viruses. Anyone know what could be wrong?