A variant of the Vundo trojan is known to cause Firefox to have problems loading certain websites. Symptoms of this infection include:

• Problems loading certain high-traffic sites, including Google, Yahoo, MySpace, Facebook, and more.
• The affected pages never load - the Firefox activity indicator may spin for several minutes, or the status bar may show "Done" on a blank page.

If you're having a problem loading sites other than the one described above, see the Error loading web sites article to see if it addresses your problem. You can also check your Internet security software - resetting permissions for Firefox can often fix similar problems.

There can be other causes of the symptoms described above. Before attempting these instructions, try the methods described in the Basic troubleshooting article to see if they will address your problem.

Search for malware

Not all variants of the Vundo trojan can be detected or removed by malware scanners. However, you should scan your computer for infections first:

• Run the Microsoft Malicious Software Removal Tool.
• Run a full system virus scan with something other than your normal program:
  • A free solution online is Kaspersky's online scanner.
• Run a full system spyware scan with something other than your normal program:
  • MalwareBytes' Anti-Malware
  • SUPERAntiSpyware is known to detect many variants of Vundo, and has a free version.
  • Spybot S&D is a well-known free solution.

More help

If you still have problems after scanning, you may ask a support question.

There are also specialized forums for malware removal such as those listed below, where you might be able to get more help:

• Bleeping Computer Forums
• Safer Networking Forums
• Spyware Warrior Forums
• SWI Forums