What could possibly make my Dell OptiPlex 780 initialize "boot itself" unexpectedly? The system will idle all day with screensaver on, if left alone. When I actually start using the system it initializes itself. It will initialize (itself) as much as I try to use it.
Are you saying that if your system is in screensaver mode, it will just reboot itself when you move your mouse or press a key on your keyboard? I am having a hard time understanding what you mean by "initializes itself".
At any rate, I would try
- shut down system,
- remove the power cord
- press the power button for 30 seconds
- remove the battery from the motherboard
- wait 15 minutes then put the battery back in (maybe even use a fresh battery)
- plug the power cord back in
- boot into bios and load in default settings as well as adjust the date and time
- reboot back into Windows and see if the problem went away.
the computer runs for only a few minutes (like 2) after you start inputting or open up word, etc. The screensaver comes on and can run all day but if you start making the computer do what it's supposed to do, it initializes or boots (turns off by itself) and restarts (turns back on by itself).
There could be many things that could cause this, but one thing is faulty hardware. You should try what I suggested above.
If that fails, you should remove everything from the inside of your PC except one hard drive & one stick of ram. If you have on-board video, remove your video card (if you are using one) and use the on-board video for the moment. Remove all external devices except your keyboard and mouse. Then power up and see what happens. If everything is working OK, shut down and add something back then reboot and try again. Keep doing this until (hopefully) you find out which piece of hardware is causing this to happen.
If you cannot find any hardware that's making this happen, then it is possible (slight chance) that your BIOS is the problem. If you are comfortable with flashing your BIOS with the latest version (even if you already have the latest version), do it.
Then there is the issue that it could be a faulty power supply, CPU or motherboard. There is no easy solution for this except replacement, which can be costly. Well, the motherboard and CPU can be costly. A decent 450W-550W power supply can be purchased for $50 or less, brand new. If it can be determined that your power supply is the problem, you just have to make sure that your Optiplex 780 uses a standard ATX power supply and that the pinout of the power supply is also standard. If it's not, then you may be reduced to having to buy a used or refurbished OEM power supply, which I never recommend. But unfortunately, unless you have a known, good power supply laying around, it's going to be hard to diagnose if your motherboard or CPU or power supply is the culprit. You have to try to rule out everything else until you are down to deducing that it is either the motherboard,CPU or power supply. Then, try another power supply (known to be good) and if it works, it's the power supply, if it doesn't, it most likely the motherboard or possibly the CPU.
There are other things that could make your PC reboot, including malware (good idea to make sure you scan your system for malware), but these are probably the major ones.
I found an article which helps to identify various reasons and some solutions for this problem. www.thewindowsclub.com/windows-computer-restarts-without-warning
However, I would NOT disable automatic restart upon system failure as the article suggests at the beginning. Doing so might cause whatever is causing the restart to damage good components of your system.