If I write zeros to my hard drive, will the hidden partition be formatted with the entire hard drive ? Or the hidden partitions will stay untouched ?
Writing zeros to a hard drive will cause reinstallation (reformatting) of an operating system on a boot drive. Users should do this only when they want a blank drive.
This means that the drive will be completely wiped clean and all partitions, regardless of whether they are hidden, will be gone.
There are several advantages to doing so. When a hard drive is reinstalled or reformatted, it is checked for errors and prepared for use. This is a good option if the drive in question was passed on from a previous user; if it had been infected with malware or virus(es), if it has software problems, or a fresh start is required before a new installation of an operating system.
Backing up of important files is recommended if reformatting of a hard drive is required.
Please note that formatting doesn't securely delete the contents of a hard drive as data can be recovered through the use of available tools.