|Power failure events can produce power spikes or power surges that can damage the power supply or the mboard or anything connected to the mboard. If it was caused by a lightning strike nearby or to the AC power grid, it's even more likely something was damaged.|
Your Youtube reference sounds like the typical beep pattern you hear for a ram problem or no ram installed, although it's likely with your bios that the long beeps are shorter - about a half second each. The beep pattern is probably identical to that when no ram is installed.
Your ram may or may not be damaged - something else may be damaged, including the power supply.
It's not likely more than one ram module would be damaged at the same time.
You could try the ram modules in another computer's mboard that the ram modules are compatible with. If they work fine there's nothing wrong with them, however, if they don't work fine that doesn't necessarily indicate they are bad - they must be compatible with being used in the mboard you plug them into.
Try another power supply if you can.
Unplug the wiring connectors, the video card, the ram modules, one by one and look for evidence of physical damage - damaged wiring metal end connectors, pins, or contacts.