Firefox Crashing/Freezing Constantly and Resetting to Defaults

Question

For the past few weeks, I have been having a lot of issues with Firefox crashing. Every time I try to open up a new tab or load a web page it will freeze. Sometimes this is only for a few minutes, while other times this lasts up to an hour and I have no choice but to close the program out using the task manager, as any attempts to close it normally fail. This is most prevalent within the first few minutes after I launch Firefox, and the program has been slow in this regard for quite a while, though usable after waiting a few minutes for it to fully load. As I stated though, for the past few weeks it has been completely locking up and crashing when this happens, and it continues to happen after I have already loaded web pages and try to open new ones.
I tried a complete fresh install, and the problem was fixed for a few days, however, after going for a couple of days without internet access and trying to get online again, the problem returned even worse than before. More than that, now from time to time my Firefox completely resets to default settings, clearing out my "New Tab" page's pinned tabs, as well as removing whichever theme I had applied.
This glitch has rapidly made Firefox unusable for me, which makes me very upset as I far prefer it to Google Chrome. While I don't know that it would help discern the issue, below is also a list of all the extensions I have installed as well as the plugins I have that are always active, (with all my other plugins either being disabled or "ask to activate"). With the exception of "Adblock Edge", I have had all the extensions installed for several months with no issues. "Adblock Edge" itself I only installed after uninstalling and reinstalling Firefox to try and fix my issue. My current Firefox version is 35.
Extensions:
Adblock Edge 2.1.7
DownloadHelper 4.9.24
Private Tab 0.1.7.3
Adblock Plus 2.6.7
Plug Ins:
Shockwave Flash 16.0.0.296
Unity Player 4.6.1.51269

Answer 1

Do a malware check with several malware scanning programs on the Windows computer.
Please scan with all programs because each program detects different malware.
All these programs have free versions.
Make sure that you update each program to get the latest version of their databases before doing a scan.
*Malwarebytes' Anti-Malware:<br>http://www.malwarebytes.org/mbam.php
*AdwCleaner:<br>http://www.bleepingcomputer.com/download/adwcleaner/<br>http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
*SuperAntispyware:<br>http://www.superantispyware.com/
*Microsoft Safety Scanner:<br>http://www.microsoft.com/security/scanner/en-us/default.aspx
*Windows Defender:<br>http://windows.microsoft.com/en-us/windows/using-defender
*Spybot Search & Destroy:<br>http://www.safer-networking.org/en/index.html
*Kasperky Free Security Scan:<br>http://www.kaspersky.com/security-scan
You can also do a check for a rootkit infection with TDSSKiller.
*Anti-rootkit utility TDSSKiller:<br>http://support.kaspersky.com/5350?el=88446
See also:
*"Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked
*https://support.mozilla.org/kb/troubleshoot-firefox-issues-caused-malware