If you need to upgrade Windows 10 Home to Windows 10 Pro you should do it by clicking on the Windows Logo (start button), Settings (the gear icon), Update, Activation, and then click go to store.
WHEN IT DOESN’T WORK: Sometimes when you do this it will just take you to the generic windows store page rather than taking you to a page specifically for Windows 10 upgrades. If this happens you will be unable to find the Windows 10 upgrade in the store as it isn’t normally listed. Microsoft say that this problem is usually caused by Antivirus products interfering in the way they launch the Windows store from the settings page. So, temporarily disable your anti-virus for 10 minutes and use this time to click on the Go to Store link on the activation page again. This should now take you to the correct page in the Windows store where you will be able to make the purchase.
If you are using someone else’s credit card to process the upgrade this will have to be done by logging into the store using your microsoft account, entering the credit card details, completing the purchase, and then, from any computer, going to https://accounts.microsoft.com, logging in using that same microsoft account and removing the credit card details from the account so that it isn’t accidentally used to purchase other items from the Windows store in future!
Credit card note: You will need to have a credit card that corresponds to the country that your computer is located in (using the region page in settings on your computer), if you don’t, you will need to change the region settings and go back to the store page to try the purchase in the same currency as the credit card is billed in. Note that Microsoft’s exchange rates may significantly differ from official exchange rates as it looks like they may have set the prices against the US$ at the time the product was released to market, rather than varying it as exchange rates vary. Therefore it might not always cost the equivalent of $99.99 USD, and some countries/states impose taxes on top of that. So don’t be surprised if there is some variation in the price.
Once you make the purchase it will check that you are ready to go ahead with the upgrade and then it will prepare the upgrade and count from 1% preparation to 100% preparation. The 100% point often lasts for more than 1 hour! (I’m not sure where they get their understanding of preparation and 100% from as you would expect it to be prepared by the time it reaches 100%.)
After time passes, it will then reboot the computer and will very quickly complete the upgrade process and then you will be able to use the computer again.