Lifebook E782 laptop switches off after every 10 minutes.

Hello. This is my first time on the forum and I do not know if this has been covered before. I have a lifebook e782 laptop. One day I switched it on while there was some water underneath. It showed a blue screen. I then let it dry for 3 weeks. Now when I switch it on, everything works but it switches off every 9-10 minutes. The fan is high speed from switching on. I have checked the cpu temperature with speedfan and core temp. It switches off when the temperatures are about 59°C on both cores. I have opened it and put new thermal paste and switched it on. By the time it switches off the heat sink is only warm. I have switched it on without the hard drive and it still switches off. I have alternated the ram memory modules one at a time in different slots. The result is the same. I have checked memory diagnostics and it says no problems found. I have switched it on in safe mode and the result is the same. I have switched it on with either the PSU or the battery. Same result. I have set the power options not to switch off at all and no hibernation. Same result. I cannot think of anything else to do. For 10 minutes everything works like normal. Once it switches off, I switch it on again immediately and it is another 10 minutes before it switches off. I cannot find anywhere where it is set to switch off after 10 minutes. Maybe someone knows what the problem is. Thanks in advance