I want to install a new Ubuntu on a drive where a previous Ubuntu system is already installed beside Windows7.
The first option says that only Ubuntu will be replaced.
The second says that all will be erased.
I only want Ubuntu replaced with the new one while keeping Windows7 untouched.
Is the first option (“Erase Ubuntu16.10 and reinstall”) the good one in this case?
The Erase Ubuntu and reinstall option in the Installation type screen of the Ubuntu installer will erase Ubuntu and reinstall it over the existing Ubuntu partitions without overwriting Windows if Windows is installed alongside Ubuntu.
This was reported as a critical bug in Ubuntu 13.10: Install/reinstall wipes out all/other partitions and a fix for this bug was released in the Ubuntu 14.04.2 point release.
Personally I choose "Something else" part and format my main Ubuntu partition and install on that partition, never see an error after that.
It shouldn't pose any problems, but just in case the best would be for you to backup your disc. In this blogpost there's a how to guide for cloning your hard drive using the Ubuntu live cd. Whenever you are playing with partitions you have to be careful.
