Javascript errors in browsers

resource:///components/nsprompter.js:466
My advice is to try a new Profile (don't delete your current Profile) and see if there is any improvement.
http://kb.mozillazine.org/Creating_a_new_Firefox_profile_on_Windows
Are all of your plugins up to date?
1. Click on the Firefox Button and click on "Add-Ons".
or
1. Click Tools then click "Add-Ons".
2. Click on the "Plugins" tab on the left.
3. Click on the link at the top that says "Check to see if your plugins are up to date."
http://kb.mozillazine.org/Unresponsive_Script_Error
You can also try to delete or rename mimeTypes.rdf in the Profile Folder
See also http://kb.mozillazine.org/File_types_an ... ad_actions (Resetting_download_actions)
...

Resetting download actionsThis section applies to all versions of Firefox and Mozilla Suite/SeaMonkey
If problems arise or if you want to restore the default set of file download actions, do the following [6]:

1. Type about:config into the address bar.
2. Find the preference browser.download.pluginOverrideTypes and, if it is present, right-click on it and select reset.
3. Find the preference plugin.disable_full_page_plugin_for_types and, if it is present, right-click on it and select reset.
4. Open the profile folder. (The profile folder is hidden by default in Windows 7/Vista/XP/2000 and Linux; read this for help finding it).
   Note: In Firefox 3.6 and above you can open the profile folder from the Firefox menu, via "Help -> Troubleshooting Information".
5. Completely close your Mozilla browser.
6. Delete (or rename) the file mimeTypes.rdf.

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http://www.techspot.com/community/topics/possible-malware.183498/
For x32 (x86) bit systems download Farbar Recovery Scan Tool 32-Bit and save it to a flash drive.
For x64 bit systems download Farbar Recovery Scan Tool 64-Bit and save it to a flash drive.
Plug the flashdrive into the infected PC.
Enter System Recovery Options.
To enter System Recovery Options from the Advanced Boot Options:

• Restart the computer.
• As soon as the BIOS is loaded begin tapping the F8 key until Advanced Boot Options appears.
• Use the arrow keys to select the Repair your computer menu item.
• Select US as the keyboard language settings, and then click Next.
• Select the operating system you want to repair, and then click Next.
• Select your user account an click Next.

To enter System Recovery Options by using Windows installation disc:

• Insert the installation disc.
• Restart your computer.
• If prompted, press any key to start Windows from the installation disc. If your computer is not configured to start from a CD or DVD, check your BIOS settings.
• Click Repair your computer.
• Select US as the keyboard language settings, and then click Next.
• Select the operating system you want to repair, and then click Next.
• Select your user account and click Next.

On the System Recovery Options menu you will get the following options:

• • Startup Repair
    System Restore
    Windows Complete PC Restore
    Windows Memory Diagnostic Tool
    Command Prompt
• Select Command Prompt
• In the command window type in notepad and press Enter.
• The notepad opens. Under File menu select Open.
• Select "Computer" and find your flash drive letter and close the notepad.
• In the command window type e:\frst.exe (for x64 bit version type e:\frst64) and press Enter
  Note: Replace letter e with the drive letter of your flash drive.
• The tool will start to run.
• When the tool opens click Yes to disclaimer.
• Press Scan button.
• It will make a log (FRST.txt) on the flash drive. Please copy and paste it to your reply.

Next...
Re-run FRST again.
Type the following in the edit box after "Search:".
services.exe
Click Search button and post the log (Search.txt) it makes to your reply.
I'll expect two logs:
- FRST.txt___________________

Download attached fixlist.txt file and save it to the very same USB flash drive you've been using. Plug the drive back in.

Attached Files:

• fixlist.txt

NOTICE: This script was written specifically for this user, for use on that particular machine. Running this on another machine may cause damage to your operating system
On Vista or Windows 7: Now please enter System Recovery Options.
On Windows XP: Now please boot into the UBCD.
Run FRST/FRST64 and press the Fix button just once and wait.
The tool will make a log on the flashdrive (Fixlog.txt) please post it to your reply.
Next....
Restart normally.
Please download ComboFix from Here, Here or Here to your Desktop.

**Note: In the event you already have Combofix, this is a new version that I need you to download. It is important that it is saved directly to your desktop**

• Never rename Combofix unless instructed.
• Close any open browsers.
• Close/disable all anti virus and anti malware programs so they do not interfere with the running of ComboFix.
• Very Important! Temporarily disable your anti-virus, script blocking and any anti-malware real-time protection before performing a scan. They can interfere with ComboFix or remove some of its embedded files which may cause "unpredictable results".
• Click on this link to see a list of programs that should be disabled. The list is not all inclusive. If yours is not listed and you don't know how to disable it, please ask.
• Close any open browsers.
• WARNING: Combofix will disconnect your machine from the Internet as soon as it starts
• Please do not attempt to re-connect your machine back to the Internet until Combofix has completely finished.
• If there is no internet connection after running Combofix, then restart your computer to restore back your connection.
• Double click on combofix.exe & follow the prompts.

• NOTE1. If Combofix asks you to install Recovery Console, please allow it.
  NOTE 2. If Combofix asks you to update the program, always do so.

• When finished, it will produce a report for you.
• Please post the "C:\ComboFix.txt"

**Note 1: Do not mouseclick combofix's window while it's running. That may cause it to stall
**Note 2 for AVG and CA Internet Security (Total Defense Internet Security) users: ComboFix will not run until AVG/CA Internet Security is uninstalled as a protective measure against the anti-virus. This is because AVG/CA Internet Security "falsely" detects ComboFix (or its embedded files) as a threat and may remove them resulting in the tool not working correctly which in turn can cause "unpredictable results". Since AVG/CA Internet Security cannot be effectively disabled before running ComboFix, the author recommends you to uninstall AVG/CA Internet Security first.
Use AppRemover to uninstall it: http://www.appremover.com/
We can reinstall it when we're done with CF.
**Note 3: If you receive an error "Illegal operation attempted on a registery key that has been marked for deletion", restart computer to fix the issue.
**Note 4: Some infections may take some significant time to be cured. As long as your computer clock is running Combofix is still working. Be patient.
Make sure, you re-enable your security programs, when you're done with Combofix.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NOTE.
If, for some reason, Combofix refuses to run, try one of the following:
1. Run Combofix from Safe Mode.
2. Delete Combofix file, download fresh one, but rename combofix.exe to your_name.exe BEFORE saving it to your desktop.
Do NOT run it yet.
Please download and run the below tool named Rkill (courtesy of BleepingComputer.com) which may help allow other programs to run.
There are 4 different versions. If one of them won't run then download and try to run the other one.
Vista and Win7 users need to right click Rkill and choose Run as Administrator
You only need to get one of these to run, not all of them. You may get warnings from your antivirus about this tool, ignore them or shutdown your antivirus.
* Rkill.com
* Rkill.scr
* Rkill.exe

• Double-click on the Rkill icon to run the tool.
• If using Vista or Windows 7 right-click on it and choose Run As Administrator.
• A black DOS box will briefly flash and then disappear. This is normal and indicates the tool ran successfully.
• If not, delete the file, then download and use the one provided in Link 2.
• If it does not work, repeat the process and attempt to use one of the remaining links until the tool runs.
• Do not reboot until instructed.
• If the tool does not run from any of the links provided, please let me know.

Once you've gotten one of them to run, immediately run your_name.exe by double clicking on it.
If normal mode still doesn't work, run BOTH tools from safe mode.
In case #2, please post BOTH logs, rKill and Combofix.
DO NOT make any other changes to your computer (like installing programs, using other cleaning tools, etc.), until it's officially declared clean!!!