I had this same problem about 6 months ago. To resolve it I reseated the RAM or switched the slot I can't remember exactly. Now the same computer is back again with the same problem. Beeps three times pauses beeps again then solid power light but no video.
I have resolve the issue by removing the power adapter and unplugging the battery then holding down the power button for a few seconds. Reconnect everything and all is well.
My question is what is causing this?
Verified disk and permissions just because.
Thanks in advance.
OS is 10.8.5