Ubuntu not getting installed showing sacrifice children error

[Hitarth]

I was trying to clean boot my pc using bootable usb & suddenly the power was off and later when I restarted my pc it was not even entering the installation mode. It is showing errors like :
1. ACPI PCC probe failed
2. [sdb] no caching mode page found
3. Out of memory: kill process 126 (systemd udevd) score 132 or sacrifice child
and similar errors.
I have already done memory & disks check( using the ones which came along with my pc by deafult ) and they all are showing passed still no installation proceeds & for either of the options - try or install errors as shown in this image are coming up. There should not be any memory shortage as I have 8GB ram, 1tb harddisk & i5 processor. Infact, the BIOS is also showing 8GB ram only.
It is very urgent & I will be very grateful to anyone who helps me.

[brian-mccumber]

If it is a desktop try - turn it off, unplug the power cord and hold the power button down for like 30 seconds. You can do the same if it's a laptop but you have to unplug it and remove the battery then hold the power button down. Then plug it back in and try to boot using your bootable usb. If that doesn't work your bootable media may have been corrupted when the power went out so you may have to remake it.

[grahammechanical]

Linux prints system messages to the screen. Most of them are covered by a splash screen. Those messages are not necessarily error messages. Even messages that say "failed" often do not stop the loading of the OS.

ACPI PCC probe failed is a common message that first appeared on our screens about half way through the development period of 15.04. I was running the development version of 15.04 at the time. I am now running the development version of 15.10 and that message does not show up. And I have not made any changes to my machine. Do not see that message as a problem.

Likewise, the other messages may not be things that stop the loading of the OS. They do prove that Linux is loading for they are Linux messages. I do not think that the "out of memory" message has anything to do with the amount of RAM. I would guess it has more to do with some allocation of memory assigned by the SystemD init system to some SystemD process or other.

I do not understand what you mean by "installation mode." Do you mean a boot menu? If Linux is the only OS on the machine then we will not see a boot menu. The boot loader will still be there and it will load Linux without showing a boot loader menu.

Does Linux load to a login screen and a working desktop environment? You do not say. If everything is working fine, then do not worry about those messages. If Linux is not loading to a working desktop, then that is the problem that has to be resolved.

What version of Ubuntu are you using? Is there another OS on that machine? I do agree with the suggestion that powering off a computer with a USB stick still plugged into the USB port will corrupt the files on the USB stick.

Regards.