The computer is already running Windows 8 and Ubuntu, but the latter is not in working condition (details about the inoperability can be viewed in my last question ), booted from the USB flash drive, copied the /home directory to the data section, try to reinstall Ubuntu, but it hangs at the moment " Preparing to install Ubuntu "also pops up an incomprehensible alert.
What's wrong? How to fix this?
It also wonders if an existing grub will be killed, in which there is a download point for Windows when reinstalling ubunt?
PS With ubuntu poking around 4 days, the answer I would like to get the most detailed. If you need to climb somewhere and see some logs, please write how to climb, etc. Thank you in advance!

memtestin grub, 20 minutes is enough to work, if there are no errors, you can exit without waiting for completion) and the file system (fsckin recovery mode). Prior to that, the installer worked, and now stopped? - federk