I'm not sure what it could be. I suppose trying to plug the unit in a different outlet would seem redundant, but have you tried that?
If not, it sounds like a repair issue. I have no idea what could have caused that. It could be anything from a power spike to the power supply giving out. It's mere speculation, but that's the best I can do with the information provided.
I wish there was a secret reset button, but I don't have anything up my sleeve that could diagnose this.
After 4 years of good use my Samsung v3650 suddenly will not power up from the unit or remote after confirming the outlet(s) are hot. A VHS tape is stuck inside. I don't know if this has anything to do with it but wanted to mention this. Does anyone have suggestions what the problem is?