I am using a 64bit fresh installation of windows 8.1 laptop with the latest 27.0.1 version of firefox. I have been getting start up error messages. The messages claimed that each of nss3.dll, mozglue.dll,plc4.dll,plds4.dll could not be found in windows. I found a good fix explanation on a site where I could download these missing files and copy them to the system folders on windows (in sytstem32 and sysWOW for 64 bit) Each time the error message popped up the next dll file missing and most recently the message has changed to “ command.exe entry point not found” NSSUTIL_DoModuleDBFunction dynamic link library softokn.dll As I can find no reference to this on the net I was hoping you might be able to shed some light on the problem. I have tried reinstalling and I have also tried the reset option in troubleshooting but the problem remains after restoring my FF backup settings. A completely fresh installation does remove the problem but the first installation of a new extension add on (but seemingly not plug-in) and the problem returns regardless of which add-on.