I suggest that you try to find out if you have any warranty by requesting an rma. Chances are that the power brick didn't filter out any spikes and passed it on to the monitor's board. If there is no warranty at all you could take a look inside for burn marks and bad caps.
I recall there is a 1 year warranty on Samsung monitors. You can try to contact them for an RMA and even if it is not under warranty they may offer a replacement at reduced cost. However it is not the function of the "power brick" to protect from line surges or fluctuations. It is only a transformer used to convert to wall outlet line AC power to a lower DC power that the monitor uses. It is always advisable to have every piece of your system plugged into some type of surge protector. It is possible that even though the main system is protected a sure or lightening spike can travel to cause damage across the connecting cables. GL
Sounds like the back light may have died. My LG had the same symptoms when it gave out, but I was sitting in front of the screen when it died. I saw it dim then just lost all picture. Windows still detects it and acts like its there, the monitor light still comes on and I can see it go from orange to blue like its getting a signal, but nothing comes up on the screen. I ended up having to replace the monitor.
When I leave, even for a weekend, I unplug all electronics, modems etc (it's only 4 outlets to unplug and a cable modem cable to disconnect for me).
I would agree, probably the electronics for receiving the HDMI signal have been fried. The display panel is still working (since you see the HDMI box), so it maybe something you could fix or find a part for maybe.
But first, go through the rest of your electronics, make sure everything else works, maybe go as far as stress testing your PC. If you have more stuff lightning damaged, you should be able to claim against homeowners or renters insurance, but if it's just the monitor your better off just fixing/replacing it.