Computer Booting Up At Midnight

Hi, I recently purchased a refurbished Dell Optiplex 9020. It is now out of it's original warranty and the insurance I bought won't cover it unless it stops working, so I'm trying to fix it myself.

Ever since I've had it it boots up at midnight. As far as I know I have turned off everything under device managers, lock screen settings, even went into the bios to turn off any auto starts. The bios expedition was yesterday, and last night it still booted up.

If anyone has any ideas whatsoever, please let me know, even if I've tried them before, I might check them out again to see if I did it right. This is just really annoying as I sleep in the same room as my 'office'.

I've also had some problems with the screen flashing random colors, usually when it wakes up from sleep. I've disabled all the sleep stuff, but it will still occur sometimes after the automatic boot ups which is really annoying.

Thanks in advance for your insight.

 

It most likely is a scheduled scan by your security software. You can check your Task Scheduler. Alternatively, you will have to power off the computer using the master power switch on the back of the PSU.

 

Thanks I'll try these suggestions. Going thru the task scheduler will take awhile, it looks like, but maybe it's in there. I had already tried the device manager, but I looked at it again and it seemed a couple of the magic packet ticks had reappeared. I deselected them (again) and hopefully this works.

Thanks so much for the advice. This has been such a needle in a haystack. I would have thought that when the software was reinstalled in the computer they would have reset it to defaults.

On edit: I will be using the power switch in back if I need to. Thank you for reminding me of it!