Firefox annoying problem

I am running XP Pro on my desk computer and using firefox browser for more than five years with no problem.
Today I found out a very annoying problem:
When I am clicking on the icon to open the browser, the browser open and everything work smooth, but if I click again on the icon to open a second one (when the first one is still open) in order to browse with both separately , the browser does not open ( not responding). I can click on the firefox icon with no reaction, i.e. I have only one tab open and cannot open a second one
If I exit firefox (close the open tab) I cannot reopen the browser . In order to open it again , I have to restart the PC.
I uninstall the firefox program and reinstall it again, but above issue remain.
I cleared the ProfileManager and reinstalled the program , same issue.

Need assistance. Thanks

 

Can you use File-->New Window(Ctrl+N)?

 

If you can't, take this downstairs to the-edmeister. With another profile, there's -no-remote.

 

Thanks for your prompt answers

Where is this file located? and how to use Ctrl+N

Open "Tools" --> Add-ons --> Extensions
The add-ons listed there are:
- IDM - Internet download Manager
- iMesh Mediabar
- Java console 6.0.15
- Java Console 6.0.14
- Java Quick Starter 1.0
- Microsoft .Net framework Assistant 0.0.0

Are these the add-ons I have to disable?

 

update your Java to the latest 6.0.20 and remove old installs via Add/Remove programs. The version(s) you have have security issues

 

Hello Sadeghi85 and GlobalForce

I asked my kid if he ran or install any program for the last two days.
I was told he ran "a-squared" (free program) manual scan but removed all the findings including the "low-risk" ones which are not automatically sticked (for removal) by the program, but left to be sticked at the user discretion.
I want to the quarantine of a-squared and found out some Mozilla "cookies.sqlite"' remove from Mozillz\Firefox\Profiles and also a file C:\.....\Mozilla Firefox\extensions\{B7D3E479-........35F419}\chrome\imeshmediabar.jar
I restored the last one from the quarantine, restarted the PC.... which solved the issue.

Note:
a-squared mentioned the file above as "Riskware.AdWare.W32.Mostofate!IK" while other protection programs (Nod32, Malwarebyte, etc.) are not detecting it. Is it a false positive detection?
I am myself running a-squared very seldom, for information only, being told it has a lot of false positives detection.

Thanks a lot for your time

 

Thanks Cudni for your remark
the Add/Remove programs showed only "Java(TM)6 Update15"
I installed the update 20 which installed and override (discarded) the existing one.
Thanks

 

Hi Samy,

I take iMesh is something your kid runs on the family computer, an item you're comfortable with?
How about the rest of it - anything other than that suspect file concerning you?