Major Windows 10 Problems And Solutions

AUTOMATIC WINDOWS UPDATE (FIXED ON CREATORS EDITION)
This, obviously tops the list of "Reasons why you should not upgrade to Windows 10 yet" found on many websites. Here is the way around to turn it off. (Only problem is this does not work on the Home edition but every other edition works fine). I'll edit to add trick for Home edition users later
To turn off automatic updates; press Windows Key + R, type "gpedit.msc" and press enter, Navigate to
Computer Configuration\Administrative Templates\Windows Components\Windows Update.
Locate the "Configure Automatic Updates" setting in the right pane and double click it. Set it to "Enabled" and select your preferred setting. Save the change.
P.S: Windows update seems to notice the change after you click "Check for Updates"

SEARCH RESULTS ONLY FROM C DRIVE (FIXED)
In this new version of Windows, Microsoft introduced Cortana personal assistant which also serves as a local/Web search for your PC. The problem is that cortana searches for contents only on the drive you installed Windows which is usually C: drive. People with a single partition will not notice this problem but it's a sure nightmare for guys with double or multiple partitions like myself knowing that I can't see a file am looking for in drive D:
How to solve this; Goto Control panel (right click on windows Icon) -- Indexing Options -- modify -- [select drive(s) you want cortana to search] -- OK
If the drive has already been index before then select it from the lower pane, click OK-- Advanced -- Rebuild
Then wait for it to index the files in the drive. When it's finished, Cortana can now see them

DEFAULT SEARCH ENGINE IN EDGE BROWSER
With the new Windows, Microsoft debuted their all new browser named Edge. I used to be a fan of Firefox but after this upgrade I couldn't get enough of Microsoft Edge. There are a lot of new features you'll really enjoy in this browser but the only con is the default search engine which is Bing (since a lot of us are happier with Google). Here's how to change it to Google.
First visit Google.com from the address bar then click the three dots at the extreme top right (just under the close icon) then click settings then "view advanced settings". Scroll down to "search in the address bar with" and click the box. If you had visit Google website, it'll appear there, then select it

GOING BACK TO YOUR PREVIOUS WINDOWS
This option is only available to those who upgraded from windows 7 or Windows 8.1. If you performed a clean install then skip this number.
For one reason or the other you might want to go back to your former windows. Microsoft prepared a downgrading tool for you. Just click on Windows Icon and in the start screen, click on settings then update and security and click on recovery on the left pane. Depending on your former windows version, you'll see "Go back to Windows 8.1 (or 7)"
Note that this feature is only available for a month because Microsoft deletes your "windows.old" folder after a month so apparently you have a month to decide if you're gonna stick with windows 10 or not.

CORTANA SEARCH BAR ON THE TASKBAR
This is one of the first things you notice immediately after upgrading to Windows 10. The cortana search bar being in the Taskbar may be cool for some but to others, unnecessary. Here's a short way to hide it or turn it to Cortana icon. Right click on the bar and select "search" (if you've activated cortana, you'll see cortana instead of search) then from the sub menu click "Show search as icon" or "hidden".

DISPLAY DRIVER PROBLEM (SCREEN BRIGHTNESS NOT WORKING OR SLEEP MODE MISSING)
This problem occurs because during the update, Microsoft uninstalls your display driver and installs the basic display adapter for you.
The solution is to install your display driver back. You can do this by either

checking for Windows update and updating your system

Go to device manager and right click on display driver and update using internet

Download driverpack solution or any driver installation software

BATTERY DISCHARGING VERY FAST(FIXED. ONLY FIRST GEN PROCESSORS ARE AFFECTED)
Sadly this has not fully been resolved but Microsoft and Intel are continuously working on it. It has been restored on some processors so keep updating your windows, yours might be next.