I have been looking for some similar info and found this link that discusses a "firmware" update. The link is below if want to read up, it has links to the actual firmware too.
I have a Samsung Syncmaster SA350 that I've had for about a year, and today when I left for work, I just left my monitor on (it auto sleeps when I don't do anything for 10 minutes)
When I got home from work, the input was on "HDMI" which I've never had it at, as I connect through DVI. It's absolutely stuck, the source button won't do anything at all if i keep it plugged in through DVI, it doesn't even respond. If I hit the power button on the monitor and turn it off, then back on, it will say "HDMI" in the top left corner, and if I hit the source button then, it just goes black and I'm stuck again.
I tried just plugging it in through VGA, and nothing happened, same result. If I plug it into HDMI, it will give me a gray screen instead of a black screen, and allow me to hit the source button, but then it just bounces back and forth between "Analog" and "HDMI" until eventually pausing before being stuck at the "Check Signal" screen, in which it just says HDMI, and won't let me change the input again.
I can't use the menu to do a factory reset, if I hold down the menu during the "Check Signal" screen, it says that the test is good, but then nothing else afterwards. The menu button works, on occasion, but doesn't actually let me navigate the menu at all.
I tried contacting the Samsung Support number that comes up on Google, but the person I spoke to only gave me basic tips on what to do (that I have already tried) and then told me that the technical support would definitely be able to solve my issue that day. Which was great to hear, but then she ended off with the kicker that "If I pay $99 today, or $149 for coverage for the next 6 months" which is a pretty big bummer, as for $149, I could just outright buy a new monitor.
I've never had a monitor break down, or have any issues. I've always bought Samsung monitors, so I'm completely confused. I've done just about everything I can conceivably think of - and I'm totally at a loss.
I wish the Samsung support wasn't such a horrible experience though =/ It may be the reason why I no longer purchase Samsung products going forward, which totally bites.
Thanks in advance either way