Unmounted my windows partition

Mounts in /mnt do not show in Nautilus left panel.
You have to go to computer and drill down to /mnt to see it.

Did you force reboot with control alt del? You never should do that with Linux. But remember the elephants.
Never force shutdown your system. Use Alt+SysRq R-E-I-S-U-B instead. (For newer laptops they don't bother adding the SysRq print to the key, but it's the same as the PrtScr key)
Holding down Ctrl+Alt and SysRq (which is the Print Screen key) while slowly typing REISUB
R-E-I-S-U-B to force shutdown
A good way to remember it is.
Raising Skiy Elephants Is Utterly Boring ...or
Reboot System Even If Ultimately Broken ...LOL.
https://en.wikipedia.org/wiki/Magic_SysRq_key
http://kember.net/articles/reisub-th...linux-restart/

Windows 8 or later is always hibeated, and Linux will not mount NTFS read/write that is hibeated or needs chkdsk, so it will not damage the partition and then chkdsk might not be able to repair it.
Since mounted ro read/only, it would not have changed anything in Windows and the issue should not have been related to anything from Linux.

Did you change boot mode in UEFI. If Windows 8 or later, it should be UEFI and should boot if UEFI with secure boot on, or just with standard UEFI. But will not boot with BIOS/CSM mode.
How you boot a flash drive is not necessarily the same as the default boot in UEFI.
But since you said your Windows was sda2, that seems like a BIOS boot install, with sda1 as Windows boot partition. If you tued UEFI on, then it will not boot.

May be best to see details:
Post the link to the Create BootInfo summary report. Is part of Boot-Repair:
https://help.ubuntu.com/community/Boot-Info