Are you tried to upgrade windows10 directly from the windows update reservation method and it went unsuccessful? Windows update process always starts again from 0% when some error occurred at the time of download or at the time of installation. It is really annoying isn’t it!
So, Downloading the windows 10 and install it via USB is the best option. Follow the below steps to install it quickly.
1. Download the media creation tool for windows 10 from here. 64 bit version click here or 32bit system version Click here. or Check this microsoft page directly. To check the 32 or 64 bit, Type “msinfo32” in the run and see the system type.
2. Make sure you have a USB with minimum of 4GB free space, as the installation will wipe the USB and copy fresh. Also make sure the USB is empty.
3. Double click the installation file. It will show first option as upgrade your system, Choose the second option to download windows 10 for another system and choose the system version 32 or 64 bit and choose edition for ex: if you are currently having windows 7 home edition means choose windows 10 home and click next and choose the USB drive colon for ex: f: and click next-> Windows download will start.
After downloading completes, verification process will starts
then your windows 10 installation media will be created on your USB.
Upgrading your Windows 10 via USB.
Click the setup.exe file in the USB and the verification will start.
Second step: Choose “Check for updates to install smoothly” (recommended) or Choose “Install updates later” if you don’t have good internet connection or your system is already updated to latest drivers. Also, Check the privacy policy option and click next.
Third step: 
Click Accept and go to next.
Fourth step: 
If you choose to check for update in step 2, this will be done or it will skip to fifth step.
Fifth step: 
and click change what to keep
and 
choose first option if you want your files and settings and click next.
Click install, after some preparations system will restart and finish the copying and installation process.
You will now have windows 10. Ask any questions if you have via comments.
windows 10 installation error C1900101-2000C:
If you have this error then your system is full of heat, make sure you have some good air ventilator, use some good fans or air cooler while installing or else system will shut down abruptly at the middle of installation and it reverses to your previous version of windows 7 or 8.
Something happened at the time of setup error at the time of installation. 
Then, make sure your language settings is set to US English. You can set this by going to control panel and find Clock, Language and Region and Find the region dialog box and click administrative option and Change System Locale to English US and restart the system and start the application again.
