Without seeing the dump, and the other related data requested in the BSOD posting instructions, I'd just be guessing. That exception is pretty straightforward though, it means that a device (the 850 EVO) was accessed but it wasn't present. That may be a drive failure, a SATA cable issue, a SATA port issue, or even a power issue. We ask for a range of data because they provide additional insight into what's going wrong.