use can use adblock plus adons to avoid these types of adds.

Do a malware check with some malware scanning programs on the Windows computer.
Please scan with all programs because each program detects different malware.

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
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender: Home Page:
  http://www.microsoft.com/windows/products/winfamily/defender/default.mspx
• 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.

• http://support.kaspersky.com/viruses/solutions?qid=208280684

See also:

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

I ALSO have the same problem. When I ran my SECURITY software, there was a MEDIUM RISK adware in my system. I got rid of it.

When I went back online, the same crap started happening AGAIN.

I've seen ads to UPDATE my Flash player... UPDATE Firefox... One WARNING that this site could be harmful to my computer... etc...

It IS quite irritating to say the least!

I might have found the solution - seems to work for me so far.

Tools - Options - Security Then click on 'Exceptions' next to 'Warn me when sites try to install ad-ons'.

I found two 'exceptions' that Mozilla had put in itself, that seemed to relate to ads. I removed them and since then - no ad webpages opening up.

Hope this helps