Its a laptop btw. There is a separate GPU located next to the "i3-350" socket...soldered... I already removed battery, BIOS battery, both RAM slots and did the 30 second power button thingy. Screen stays black, fans start up, HDD only ticks once, the sleep LED (half moon) is lid on turning the laptop on. Cant find much about this. External monitor also has no signal. CPU slowly gets hot. Probably the board and or gfx card. I stumbled across people that removed damaged flex cables (for example USB), to easily revive their MSI laptop. This didnt help here. Starting it without RAM it at least shuts down after some seconds. Is ther maybe a desaster / crisis recovery for this laptop ?
Did you test both rams one by one ? maybe one of them is dead but since there is black screen even when connecting an external monitor evrything suggests that the problem is related to the graphic card which is probably dead. Fortunately it's a physical graphic card and not integrated one so it can be replaced easily if it turns out that it is 100% GC issue. If it was an integrated, that would have been another story.
I should have mentioned it is a laptop in the beginning (fixed that in post 1) It does not BEEP. There is no POST. Screen stays black (even on external monitor) Im aware some laptops DONT show POST on external monitor. It detects the USB thumb drive (blinking shortly) but doesnt do anyhthing else after that. Board and capacitors look clean. I will order the CPU for a last test. Because there is nothing left to test. Thanks for the link.
The "new" CPU has arrived. Sadly its also gets hot after some minutes and the screens (internal and external) show nothing. No POST, no BEEP, no HDD sounds. So either GPU or the Board. :/
Sorry to hear that. yes, there are only these 2 hypotheses left in my opinion. I will go for the motherboard as the major cause of motherborad failure is overheating.