Js3250.dll missing, when I click on Windows Explorer

[Guest]

If I have Firefox open and I double click on something on my desktop or open Windows Explorer, then Firefox closes it self when I try and reopen it it says it's missing: js3250.dll, I've done everything the forums said to do but still nothing!! I have to reinstall Firefox every time.
Most people are told to remove these two .dll's ipv6monl.dll and/or msktns.dll file, I have neither so I can't very well delete them! AVG found nothing neither did AVAST!
I really need this fixed for my simple day to day PC life
Thanks!!

[Alice]

Most people are told to remove these two .dll's ipv6monl.dll and/or msktns.dll file, I have neither so I can't very well delete them! AVG found nothing neither did AVAST!

Even if you can't find those two files (did you mean "mskvtns.dll"?) it sure looks like malware, based on similar complaints (see below).

If AVG (AVG AntiSpyware?) and AVAST didn't detect anything, it doesn't mean your system is clean, only that the malware was not detected by that software. You should visit a security forum that can recommend an online scanner or specialized malware detection tools, such as:
http://www.castlecops.com/forums.html
http://forum.aumha.org/
http://forums.spywareinfo.com/
http://www.spywarewarrior.com/index.php
http://www.wilderssecurity.com/index.php

Here's one trojan detected by Avira Antivir that deletes Firefox files (this one creates ipv6monl.dll):
http://original.avira.com/en/threats/TR ... tails.html
TR/Spy.BZub.GM - Trojan

Aliases:
• Kaspersky: Trojan-Spy.Win32.BZub.hv
• F-Secure: Trojan-Spy.Win32.BZub.hv
• Sophos: Troj/Dloadr-ASR

Side effects:
• Drops a malicious file
• Lowers security settings
• Records keystrokes
• Steals information

Files
It deletes the following files:
• %PROGRAM FILES%\Mozilla Firefox\xpcom.dll
• %PROGRAM FILES%\Mozilla Firefox\softokn3.dll
• %PROGRAM FILES%\Mozilla Firefox\nss3.dll
• %PROGRAM FILES%\Mozilla Firefox\js3250.dll
<snip>

As a temporary workaround until you can get the problem fixed, after you reinstall Firefox to restore js3250.dll and other missing files, you could try making the four Program Files\Mozilla Firefox .dll files "read-only". This may not prevent Firefox from closing when you open IE or Windows Explorer but at least it should prevent those files from being deleted by the trojan.

Related forum topics:

http://forums.mozillazine.org/viewtopic.php?t=604534
JS3250.dll Deleted Among Other Files

http://forums.mozillazine.org/viewtopic.php?t=604398
Firefox closes start internet Explorer or windows explorer

http://forums.mozillazine.org/viewtopic.php?t=527210
How to stop IE from deleting Mozilla dll files

http://forums.mozillazine.org/viewtopic.php?t=510266
file keeps getting deleted

http://forums.mozillazine.org/viewtopic.php?t=497761
Firefox Crashing

Okay recently, whenever I open "My Computer" or "Control Panel" my firefox automatically shuts down. When I try to open Firefox, it gives me this message
"this application has failed to start because js3250.dll was not found. re-installing the application may fix this problem"
<snip>
btw. when i reinstall it, it works BUT as soon as i open "My Computer" or "Control Panel", it juss shuts down and repeats the problem.

This is usually is a malware that is deleting the js3250 file.
"Go to C:\Windows\System32\ipv6monl.dll and delete it. Reinstall Firefox and it will work fine."

If it was there you should do a full scan to see if there is other remaining malware. I use ewido (now by avg) http://www.ewido.net/

Related blog:

http://anothermonkey.blogspot.com/2007/ ... x-and.html
Computers, bloody computers: Firefox and js3250.dll

I too found the ipv6monl.dll. This computer was infected with multiple trojans and other annoying spyware/malware. <snip> 8/05/2007 1:21 AM

I started having this problem this past week and reinstalling firefox would only solve the problem temporarily. Something was deleting the js3250.dll. I finally traced the problem to windows explorer - I had firefox open and I went to open explorer (e.g. - "My Computer", etc.) and firefox crashed - it was the act of opening explorer that caused the necessary dlls to disappear. I then found two dlls that had appeared on my computer within the last week. I quarantined them both and voila, the problem disappeared. I then narrowed it down to just one of the dlls - "mskvtns.dll". I haven't been able to find any information about it on the web and a file scan shows it to be clean, but since I moved it out of the windows\system32 directory, I have not had the problem anymore.
11/11/2007 11:38 AM

http://www.sophos.com/security/analyses ... muzcr.html
Troj/Cimuz-CR
Trojan

Troj/Cimuz-CR is a Trojan for the Windows platform.

Troj/Cimuz-CR creates the file <System>\mskvtns.dll and installs it as a Browser Helper Object. This file is also detected as Troj/Cimuz-CR.

Troj/Cimuz-CR creates rules for itself in the Windows firewall settings.

http://answers.yahoo.com/question/index ... 503AAetcy2
Js3250.dll missing!! When I click on WinExplorer when firefox is open!! HELP!!?

I had the exact same problem. Here's what fixed it for me: Download and install HijackThis. There were 2 unknown and/or malicious objects listed in the category 'O2 - BHO' list. BHO stands for Browser Helper Objects and malware will use them to screw with you and your system.
A tip: the objects that I fixed (i.e. deleted) with HijackThis were NOT found using a google search. My guess is that the spyware and viruses are getting more sophisticated and they actually randomize the names of the DLL files that do the damage. In other words, it will be a different file name on each individual PC.<snip>

[xmanx]

hkeyCurrentUser->software->microsoft->searchassistant->
in this I found the entries to ipv6monl.dll.
I erase it and reinstalled firefox and made the files that get deleted read only and so far ie has not crash it.
I hope this will last.
You might want to recommend registry cleaners or search the registry to delete the key to the trojan if the virus is not in the system folder.
Thanks again.

[LIMPET235]

needhelpfastinahurrymaine..
I split your "off topic" post off to here,
> viewtopic.php?f=38&t=1035605
Please don't bump these old threads.
Locking.