gfx and ram need to be there, or it won't do much.
Are the fans running ?
Surprised that the LED is lit, since that runs off the 5V line, which runs the mobo. Unless it is a warning LED, will have to check that mobo out.
So it is a power LED
If there is no POST sound, then the the problem can either be the PSU or mobo.
If you have access to another PSU try that.