Possible as there is some issues with a program doing this. Check using Malwarebytes (both of them).

Please use more than 1 scanner as each uses diff tech :

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware

Save your Report and google each before deleting anything as do not want to delete something you need, If need help :

• https://forums.malwarebytes.com/topic/9573-im-infected-what-do-i-do-now/

Post in only 1 forum, then wait.

adapterDescription: AMD Radeon HD 6800 Series driverDate: 8-3-2015 Errors in your Video Card Drivers, please update/reinstall https://support.amd.com/en-us/download/desktop/legacy?product=legacy3&os=Windows%207%20-%2064

Please let us know if this solved your issue or if need further assistance.

When you look at your default search engine setting, is it called "Bing Search Engine" or just "Bing"? (Manage Firefox search settings)

There is an issue going around where users who have installed Lavasoft/Ad-Aware Web Companion get switched to "Bing Search Engine" at every startup. To clear that:

Check in these locations (varies for 32-bit / 64-bit):

C:\Program Files\Mozilla Firefox\defaults\pref
C:\Program Files (x86)\Mozilla Firefox\defaults\pref

Any files other than channel-prefs.js are suspicious. If you find the file added by Web Companion -- dsengine.js -- or any others, remove them to a neutral location for further analysis at your leisure. Or just delete them.

Thank you