System: i5 4590/MSI Z97 PC Mate/Cryorig H7 air cooler 4x4GB GSkill Ram...from previous system EVGA GTX 960 4GB Intel 535 120gb SSD and Seagate 2TB 7200rpm... from previous system Antec 750w power supply...from previous build and about 6 years old...replaced by EVGA 650w gold today Hi guys, I am trying to track down the problem in a system I built for my Dad about 2.5 years ago. It has been stable with no issues until last month when it started crashing...usually within 15 minutes of starting the machine. After crashing it acts like it wants to reboot but gets stuck on a screen saying "Reboot and Select proper Boot device or Insert Boot Media in selected boot device and press a key." At that point turning it off and on gets it back to Windows and the cycle repeats. Sometimes it can go for a few hours without issue after the cold boot crash. So far I have refreshed Windows 10 and checked for any malware. Reset the CMOS and updated the bios to the most recent version. Checked the health and firmware of the ssd with intel ssd toolbox..70% life with current firmware. Replaced the ram with Corsair 2x4gb from a working machine. Cleaned, repasted and remounted the cooler since I decided to upgrade him to a better Corsair case I had laying around. Temps were very good before and after. Replaced with old Antec power supply with a new EVGA 650w Gold. Tried connecting the SSD to different SATA ports and used different SATA cables. Reseated all connections since I moved the system to a new case..Corsair 550D Any ideas on what might be going on would be appreciated.