What can restart the computer after turning it on?

Question

Iron

Hello! Such a trouble, Installed additional. the bar for 2GB of RAM (before that it was only 2GB) The mother supports a maximum of 4GB so she scored it completely, everything worked well, but a week later the computer began to reboot itself cyclically several times in the morning after turning it on, the BIOS is loaded (you can see that it recognizes 4096MB of memory) then as soon as Windows starts loading, it immediately starts rebooting, and so on 2-4 times in a row, then once again after rebooting, the system boots normally as it should. There are no error reports, extraneous sounds, and the like, there are no power outages. This happens only when the system is turned on for the first time in the morning. Then all day long everything works stably.
(I sin on RAM because there were no problems before installing it, although it's strange that everything was stable for a week after installing it)
Windows - 8.1
Pentium (R) Dual-Core CPU E5300 2.60 GHz
Mother - Biostar G31D-M7
Video - ATI Radeon hd series 4300/4500 (not 4300 or 4500, namely 4300/4500)
RAM - 4GB
HDD - 500GB Silicone
bars
(The only difference is in a different color, because I could not find 1: 1 as it was before)
After buying the bar immediately curled, everything works 4GB displays as well as possible and the speed of work has increased

Answer 1

Well, firstly, just in case, we look at the frequencies / timings of the bars, compare them.
Secondly, we remove the new bar and observe for several days.
Thirdly, we remove the old bar, set a new bar and observe for a couple of days. (Points 2 and 3 can be swapped)
And there already jump from the results (maybe this is not memory at all?), To complete the picture, drive the memory with a memtest.

Answer 2

Battery

Answer 3

- Power supply
- Electrolytes on the motherboard
Consumption has increased due to additional memory, dried electrolytes and "buggy" until the capacity is gained.

Answer 4

Have you tried under other OSes?
Simply, if you say that it reboots exactly when the OS boots, then it's probably about it?

Answer 5

Since you are running on RAM, then run it with memtest.
Also, have you tried reinstalling windows?

Answer 6

if it is not confirmed that the problem is in the memory (memtests are good, but the method from the comment above, about taking it out - wait, more reliable), then I would do the following:
1) carefully read the logs
2) check the status of the HDD.