I installed my 512GB 840 Pro in March. There were no problems until yesterday when on boot my system booted to another hard drive. I thought the SSD had a problem so I tried to restore te previous days Ghost backup. But Ghost couldn't find the drive, even though Windows Explorer sees it and I am able to move data off of the drive to another drive. Unplugging the other drive resulted in the system telling me there was no bootable drive installed. The drive that was booting was one that came with the system when I bought it and I had left it installed, so when BIOS couldn't find a bootable SSD it went and found the bootable HDD. Because I need my PC for work to do I reinsialled Office and other programs on the HDD and move My Coduments, Pictures, and Office documents, etc, from the SDD to the proper folders on the HDD, and now I have a PC that runs.
But, I don't have an SSD and I got used to the fast boots and backups (15 second boot, 10 minute backup) and they're now 2 minute boots and 45 minute backups. SO my next move is to contact Samsung. If they refuse to help then I'll just have to buy a new one, at $500 a pop that gets expensive.