Is your memory in DIMM slots 2 & 4? That's the default slots for two sticks installed. I can't get the ASRock site to download a manual. Looks like that part of their site is down.
Your case could have a bad power switch or connector. Trace that wire all the way back to the connector on the front panel. I had that happen once with a case.
Disconnect all the chassis fans. Only plug in the CPU fan. There may be a short somewhere.
This post was edited on 1/23 at 2:42 pm