NIS locking up Firefox

This morning I've run into a most annoying problem. I'm running Firefox 25.0.1 and suddenly I've found that anytime I right-click a link and open it in a new tab, Firefox completely locks up and must be killed from Task Manager. NIS.exe is the culprit, and NIS becomes unresponsive at the same time as the Firefox lock-up. The two NIS processes are still running and the tray icon is still visible, but the UI cannot be opened. Firefox cannot be reopened, though firefox.exe will appear in Task Manager if I attempt to restart it.

 

I've restarted my computer 3 times already this morning because of this issue. I'm about to restart yet again to get both Firefox and NIS working. I'm posting from Pale Moon at this time.

 

Here is the problem signature from Windows:

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Description:
  A problem caused this program to stop interacting with Windows.

Problem signature:
  Problem Event Name:    AppHangXProcB1
  Application Name:    firefox.exe
  Application Version:    25.0.1.5064
  Application Timestamp:    5282f204
  Hang Signature:    87d5
  Hang Type:    128
  Waiting on Application Name:    NIS.exe
  Waiting on Application Version:    12.11.0.16
  OS Version:    6.1.7601.2.1.0.768.3
  Locale ID:    1033
  Additional Hang Signature 1:    87d5e54a1815c4a9521ed152a70ec742
  Additional Hang Signature 2:    268d
  Additional Hang Signature 3:    268d31e935a17ed791dfb72252240165
  Additional Hang Signature 4:    87d5
  Additional Hang Signature 5:    87d5e54a1815c4a9521ed152a70ec742
  Additional Hang Signature 6:    268d
  Additional Hang Signature 7:    268d31e935a17ed791dfb72252240165
--------------------------------------------------------------------------------------------------------------------------------

 

Exact same signature every time. Anyone else seeing this same issue? Anyone have any suggestions? I dread disabling all my extensions and trying to find a conflict one by one... don't have that kind of time today.