bootmgr, resetting bios

[Jumperone]

Again having problems with my crap pc..
Yesterday i turned off my pc like always. Today i turned it on but i saw this message:

https://scontent-waw1-1.xx.fbcdn.net/v/t35.0-12/13410384_1077350808997622_483925706_o.jpg?oh=969d6b56f4ad89f88b5c31e940e86906&oe=5760D0C9

so i pressed enter and pc rebooted. After that i got no bootmgr message. I clean installed windows, set everything and turned off pc. Now i turned on pc and i got same thing as earlier - message from screen and bootmgr error.
What's wrong with it this time?

 

[ahnilated]

Replace your bios battery first.

 

[Jumperone]

Before i did that next problem appeared. Pressed button to turn pc, it started but after 3 seconds turned off. After moment it turned on again, "beeped" and screen with only "bios" title on top, without any options appeared. After 2 seconds pc turns off.

Then the whole process begins again and again. Replaced battery but changed nothing.

 

[ahnilated]

Are you sure your power supply is good?

 

[Jumperone]

I tested psu with measurer about 2 months ago and it was fine. Maybe it just broken right now but i have no free psu to swap and test.

 

[Jumperone]

Voltages are ~12,06 on 12V and 5,06 on 5V line, measured today again.