Firefox not opening in Vista

This is my first posting so I apologize if I should have proceeded in a different way. I too have a problem with Firefox.

Three things happened almost simultaneously:
1. I got a message that a new version of FF was available for downloading: Firefox3.
2. I was infected with a Trojan that my spyware detected and quarantined - - CHM.Psyme.
3. When I went to use my browser Firefox2.0.0.15 the message appeared that it couldn't be loaded because the file js3250.dll was missing.

So using IE I downloaded Firefox3. The final panel of the install wizard has a box for 'launch FF now' which I left ticked. The launch did not happen and I got the same message as before - no js3250.dll.
I discovered from the mozillaZine site that there is malware that deletes
js3250.dll whenever certain actions are performed: opening a desktop shortcut or IE, or accessing the Control Panel, My Computer, or Windows Explorer.
Using Windows Explorer I found ....\Mozilla Firefox\install.log and discovered that certain files it claimed to have installed were absent:
js3250.dll
freebl3.chk
freebl3.dll
nss3.dll
plc4.dll
plds4.dll
smime3.dll
softokn3.chk
softokn3.dll
ssl3.dll
xpcom.dll
LICENCE
README.txt
My Spyware Doctor with Antivirus gives the PC a clean bill of health, as does Windows Defender.

Can anyone help me solve this problem, please?

 

Thanks Mark.
I did as you suggested and opened a thread in Malware Forum. I carried out all the instructions and posted logs of the various scans I made. The reply from chaslang said that my computer was free of any malware and that I should return to the Software forum because the the problem might be caused by my running a variety of anti-malware programs that clashed in some way and prevented js3250.dll from being installed. I tried switching them all off, deleted the Firefox setup file in case it was corrupted, downloaded a new copy and reinstalled. There has been NO CHANGE! The install.log shows the following as installed but they don't appear in the \Mozilla Firefox folder:

AccessibleMarshal.dll (I omitted to mention this one last time.)
js3250.dll
freebl3.chk
freebl3.dll
nss3.dll
plc4.dll
plds4.dll
smime3.dll
softokn3.chk
softokn3.dll
ssl3.dll
xpcom.dll
LICENCE
README.txt
There was also a message:
ERROR Registering: C:\Program Files\Mozilla Firefox\AccessibleMarshal.dll **
which may give some clue to what is happening.

 

Try a clean install of FF.
First, export your bookmarks to someplace other than the FF or Mozilla folder (Desktop)
Uninstall FF, then delete it's folder. (The folder will still contain config files.)
Now reinstall FF and import your bookmarks.

 

This link tells you what to do about it:
http://kb.mozillazine.org/Application_fails_to_start_because_js3250.dll_was_not_found

I just googled "js3250 dll" and numerous pages came up some of which may have the solution to your problem.

 

Thanks Oma.
I had looked at these pages but they're either about suspect js2350.dll files invading the computer with malware, which I haven't got, or sites that want me to download registry cleaners and promise to correct js3250 problems,
but then fail to deliver, as I found myself.

Thanks Musksnipe.
I can't locate my bookmarks. There is a file bookmarks.html but it does not seem to contain any of my many bookmarks
Uninstall says that there's nothing to uninstall.
I deleted the entire Mozilla folder.
I tried to reinstall but without success and everything that I described before happened again.

I have posted on the Mozilla Forum to see if they have any ideas.