Hi,

This is rather problem with your hardware or another software installed on your computer than with Firefox or waybe with webpage you are visiting. I can only suggest you to search on web for CCleaner and Smart Defrag or some similar software. Clean and defrag your PC. Also try to unistall any software you are not using, but be carful to not unininstall something that your PC needs to work properly. Before uninstalling anything search the web for that and try to inform what is it.

Hope it helps, Vladimir

Do a malware check with several malware scanning programs on the Windows computer. Please scan with all programs because each program detects different malware. All these programs have free versions.

Make sure that you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender:
  http://windows.microsoft.com/en-us/windows/using-defender
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  http://support.kaspersky.com/5350?el=88446

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

If cause by malware, why I kill firefox (and the plugin container) job in task manager then the computer run faster again? It seem one of the plugin run too long and cause timeout.

P/S: I use Symantec Endpoint Protection

haivnuni - phan mem ban hang

Disable all add-ons and test.

I enable only 2 plugins: Shockwave Flash 14.0.0.145 & Foxit Reader Plugin for Mozilla 2.2.3.703

Ok, try to clean your PC with CCleaner, do deep defrag and optimization with Smart Defrag, make sure you have space on your primary drive(where your OS is installed), test your memory with Memtest86+. If this doesn't help probably most painless and fastest solution will be to reinstall your Windows. Also keep in mind that Windows XP is no longer supported by Microsoft, so if you are in position to move to a newer version of Windows would be a right thing to do. If you reinstall your OS, just update OS and install drivers before you install Firefox and test it then without any other software installed.

I Installed CCleaner, do deep defrag and optimization with Smart Defrag, run all optimization with Advanced SystemCare 7 but it didn't solve the problem.

Attach is the pictures of message appear and the screenshot of task manager when firefox slowdown the system.

Boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that helps.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/