I run Firefox and on rare occasions when I'm searching the net it automatically opens Edge, can't say for sure if my search terms were MS related or not. I haven't had a problem in months.
When I first installed Windows 10 my browser (Firefox) was hi-jacked by malware "WinYahoo" it's a malicious website. WinYahoo would always open Chrome Browser (not the version your running) and redirect me to unwanted sites, in the main "liveadexchange.com. Malwarebytes would block "liveadexchange.com and flagged it as a malicous web site. I contacted Malwarebytes Help Team who were very accommodating. To make a long story short Mambam had me perform the following:
1. Update Mambam. Then click on settings > Detection and Protection, you will see a heading "Non Malware Protection" PUP & PUM. From the drop down box (PUP & PUM) select each to "Treat detections as malware"
Next run Malwarebytes
2. Next download FRST64.exe (Farbar Recovery San Tool) and save it to my desktop.
http://www.bleepingcomputer.com/download/farbar-recovery-scan-tool/
Download link for 32-bit version
Download link for 64-bit version
When FRST.exe is run it saves a log file to the same folder on the desktop (It identified WinYahoo).
If the tool warns you the version is outdated, please download and run the updated version.
• Click the Fix button just once, and wait.
3. Next Download Junkware Removal Tool to my desktop and run the program.
http://downloads.malwarebytes.org/file/jrt
NOTE:
Download Junkware Removal Tool to your desktop.
http://downloads.malwarebytes.org/file/jrt
Note: Don’t run it if you have Wondershare, ParetoLogic or MyPCBackup products, it will delete them!
*
Shutdown your antivirus to avoid any conflicts.
Right-mouse click JRT.exe and select Run as administrator
The tool will open and start scanning your system.
Please be patient as this can take a while to complete.
4. Next Download AdwCleaner, save it to your desktop and run it.
https://toolslib.net/downloads/viewdownload/1-adwcleaner/
Following the above identified, cleaned and deleted WinYahoo successfully.
Caution I would create a manual restore point and perform a system image before proceeding with the above. Read the JRT Log carefully to be sure what it actually wants to delete has your approval before hitting the delete button. It will delete .exe files should they be in libraries (My Docs) or wrong locations foe .exe files.
Good luck! If you have any doubts about performing the above contact the Malwarebytes help team. They are very helpfull and will assign a tech to walk you through the removal process.