This could mean that something on your system is opening Firefox.

Start your Computer in safe mode with network support. Then just let it sit for a long while. Anything?

Now start the computer normally. Again, just let it sit for a while.

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

So after starting in Safe Mode and leaving the computer for several hours, my browser did not open at all. Booting it up normally, however, caused the browser to once again open randomly. I also disabled my internet connection (Removed my ethernet cable) and it didn't seem to make a difference-- the browser still opened.

I'm not sure what would be causing this as I haven't installed any new software recently and none of my detection software is finding any trace of malware. I also don't see any unusual processes in my task manager. Do you have any suggestions for next steps?

You said the browser opens to a blank page. Is there an address or anything in the address box?

You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

Is Firefox the default browser?

If that is the case then try to sett another browser as the default browser.

FredMcD said

You said the browser opens to a blank page. Is there an address or anything in the address box? You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

There is no address in the window at all. It opens to a blank homepage. After following the attached article, still no results. I downloaded and used all of the scanners on that page and none of them found any adware or malware.

cor-el said

Is Firefox the default browser? If that is the case then try to sett another browser as the default browser.

Firefox was set as the default browser, yes. Upon changing it to microsoft edge (just as a test), the same thing occurred and several Edge windows opened over time on their own, also to a blank homepage.

Check the programs that are on your computer Windows: Start > Control Panel > Uninstall Programs.

Sort the list by install date. Take a screenshot of the beginning of the list and post it here.

In order to better assist you with your issue please provide us with a screenshot. If you need help to create a screenshot, please see How do I create a screenshot of my problem?

Once you've done this, attach the saved screenshot file to your forum post by clicking the Browse... button below the Post your reply box. This will help us to visualize the problem.

Thank you!

Here is a screenshot.

I don't see anything here.

Could you look into the Windows Task Scheduler and see whether you can find anything unknown that might be trying to launch web pages? These are the steps:

1. Click the Start button.

2. Click Control Panel.

3. Click System and Maintenance. Note: You also can use the search box in the upper right corner to look for schedule as a shortcut to clicking through the categories.

4. Click Administrative Tools.

5. Double-click Task Scheduler.

Now the hard part... finding anything in here. You will see a laundry list of tasks Windows is scheduled to run at various times. I'm attaching a sample screenshot from Windows 7 showing where the schedule information appears.