Built into the firmware on the laptops' motherboard is a piece of code called the Lenovo Service Engine
(LSE). If Windows is installed, the LSE is executed before the Microsoft operating system is launched.
The LSE makes sure C:\Windows\system32\autochk.exe is Lenovo's variant of the autochk.exe file;
if Microsoft's official version is there, it is moved out of the way and replaced. The executable is run
during startup, and is supposed to check the computer's file system to make sure it's free of any corruption.
Lenovo's variant of this system file ensures LenovoUpdate.exe and LenovoCheck.exe are present in
the operating system's system32 directory, and if not, it will copy the executables into that directory
during boot up. So if you uninstall or delete these programs, the LSE in the firmware will bring them
back during the next power-on or reboot.
http://www.theregister.co.uk/2015/08/12/lenovo_firmware_nasty/