Hello. I am using a Dell N4050 (a laptop). The computer is having lots of troubles powering up, and it also shuts down suddenly. I elaborate on the problem below. I ask for your help, please see the questions at the end. Background: I use the computer almost always connected to the power supply, instead of on its battery. I have been using this computer for more than 1 year; it gets around 8 hours of usage per day. The built-in keyboard no longer works since around 3 months ago when I cleansed it throughly with a wet tissue and apparently some water leaked and broke it (I was careful that no water made it past the keycaps, but the fact that it stopped working makes me think it happened). Now I use an USB keyboard. The built-in keyboard occasionally signals spurious keystrokes, so I had to block it in software. The computer has never fallen, had water dipped on it (except possibly for the ill fated keyboard cleansing) or been run on battery until charge run outs. Symptoms: 3 days ago, my computer powers off suddenly while I went to do something else. I turned it on again with no immediate problems, and it worked fine for around 30 minutes, but then again it powered off suddenly. I tried to power it on again, but this this time, after turning on, showing the "power on" LED, and making the usual boot noises for like 1 second (not enough for the BIOS splash screen to show) it powered off. I insisted trying to power the computer more than 10 times in a row, and the same thing happened every time except for a few occasions where pressing the "power on" button had no effect what so ever. I left it rest for 1 hour, with the power cable disconnected then turned it on and it worked fine for that day. Today my computer has again suddenly powered off while I was using it, in the same way as if I unplugged a desktop (but this is a laptop). I tried to power it on pressing the button more than 50 times with no success; pressing the button now had mostly no effect except for around 1/10 attempts resulting in the already described "power-up for 1 second"; then I tried all combinations of letting the computer rest (for at least 30 min each time) with and without the power cable, and trying to power it on with and without the power cable. After several hours of trying (most of it is rest), it finally powered on all the way to the OS, but powered off suddenly after ~5 min. I continued the aforesaid rest/try-to-power-on procedure. Finally, it powered on without the power cable and with the external USB keyboard disconnected, but I connected the keyboard (since it is otherwise useless) and it is currently working allowing me to write this message (>1 h uptime so far). The computer wasn't particularly stressed during, before or after either incident (I was using it for browsing with minimal CPU usage, and there wasn't any power outage, brown-out or similar, the ventilation path is unobstructed). I noticed that every time it shuts down suddenly, there is a "tick" heard, like when you connect or disconnect loudspeakers to an amplifier. Maybe it is actually made by the built-in loudspeakers ad the built-in amplifier is suddenly unpowered. There isn't the characteristic smell of exploded capacitors. In summary: The problem is that the computer suddenly powers offs, but after much trying and letting it rest, I could make it work, but I am still asking for help because I think it will soon stop working at all. Questions: What component is more likely to be causing the problem?. Is it possible that the built-in keyboard is causing a short circuit that forces the PSU to power off?. How high do you judge the possibility?. Please note that the keyboard has been broken for 3 months but the power-off problem just started. In case the motherboard is the problem, is it feasible to replace it or do I necessarily have to get a new laptop if the motherboard stops working? What can I do to try to fix or work around this problem without having to purchase new components (like resetting the BIOS and similar)?. I will have to try all that can be done to the computer, because it is extremely hard for me to get a new computer (I can't simply buy one in a local shop because I am in an exceptionally limiting situation); this is currently my only computer. Note: Please do not hesitate in using technical language. I am familiar with computer hardware, as I have assembled and serviced my former desktop computers (but they are broken and I can't repair them for the same reason I can't simply purchase a new computer). I have backups and I am aware that the hard disk and my data is likely not gone with the computer, but I do not have another computer to plug the HD or use the backups. I use GNU/Linux (commonly miscalled "Linux", that is actually the name of the kernel only). I have discarded the OS as the problem, because the problem is manifested before the BIOS splash screen shows, well before the OS or bootloader is running. Thanks in advance.