How to backup, reinstall and restore Ubuntu

[linux18]

you need to use the alternate install cd

[apoorvumang]

Also, due to some unknown reason, I am also not able to boot Ubuntu from my pen drive. It says "Boot Error". It used to work flawlessly before.
I guess there's some serious problem with my system..

[apoorvumang]

you need to use the alternate install cd

where do I get that?

[linux18]

Did you reformat the drive before using the startup disk creator or unetbootin?

[apoorvumang]

you mean the pen drive? I used USB Disk Creator (for windows). I've used it several times, it always worked. It automatically formats the pen drive before doing anything.

[linux18]

you should reformat the pen drive first, I've found out that it works much more reliably that way