Reinstall Windows 8.1 on PC with Ubuntu dual boot

Question

On my PC I already have a dual boot of Windows 8.1 and Ubuntu. Now after a while, Windows is acting a bit sluggish and I want to reinstall it. I have a lot of data which I don't want to lose, so I wanted to know if there is a safe way to reinstall Windows without messing up the dual boot and my current hard drive partitions.

If there is one, I would really appreciate it if anyone would walk me through it.

Answer 1

The data in Windows Partition will be removed if you format that partition and again reinstall the windows in same.

And you stated that you are using Dual Boot, whether you are using GRUB or Windows Loader to boot into Ubuntu, you will loose that loader, so to format without messing, here is what you should do

1. Back up your data from Windows Partition (usually C: drive), My document, Downloads and Desktop as well, to any external device, or in any other partition.
2. Install Windows 8 (or 8.1) via Boot Method, while installing make sure to also format the partition sized 350 MB (which is actually Windows Boot Loader) along with Windows Partition, and do not touch any other partition. (it means you will be formatting only 2 partition while installing Windows)
3. After Windows Installation is complete, now you need to recover Linux
4. Boot your computer via Ubuntu Live (create a USB Thumb using Unetbootin, or ask your friend to create one with their Ubuntu OS)

5. I will recommend to use this tool to recover Linux https://help.ubuntu.com/community/Boot-Repair Use Recommend Repair, and it will perform everything automatically for you. You'll be needing Internet access in Ubuntu to perform this step, as it is not available in Ubuntu by default, you'll need to download it manually after adding Repos (refer to the guide on above link)

6. everything is done without any mess.