Since 3.6 update firefox crashes while opening pdf's in webmail (xs4all)

Question

Since the 3.6 update firefox crashes AFTER pdf's opening in webmail. I can see, work and download the pdf file, but as soon as i change or stop this action, firefox crashes immediatly. I was waiting for updates, asked my provider but still not solved.
It is hard to test yourselve since you need to log in to a webmail..
== URL of affected sites ==
https://webmail.xs4all.nl

Answer 1

Ok, if a new profile profile has the same issue, it's an indicative that it's something outside Firefox that is causing this problem. This may be a plugin (they are installed outside the browser, and new profiles will have all installed plugins enabled), a virus, malware, a firewall/antivirus/security suite, or any other software outside Firefox. It's not a known issue, and I can't replicate it on my end, so you'll have to search for the cause yourself. Do be aware that Firefox's update may have broken something in how other software gets along with Firefox, and that may be the cause of the crashes. Malware too, so do clean your system.
To scan for malware, install, update and run these programs ''in this order''. They are all free for personal use, but some have limited functionality in their "free mode", but the features you'll miss are not really needed to find and remove the problem you have. Remember that ''not all programs detect the same malware''!
Malwarebytes' Anti-Malware - [http://www.malwarebytes.org/mbam.php malwarebytes.org/mbam.php]
SuperAntispyware - [http://www.superantispyware.com/ superantispyware.com]
AdAware - [http://www.lavasoftusa.com/software/adaware/ lavasoftusa.com/software/adaware]
Spybot Search & Destroy - [http://www.safer-networking.org/en/index.html safer-networking.org/en/index.html]
Windows Defender - [http://www.microsoft.com/windows/products/winfamily/defender/default.mspx microsoft.com/windows/products/winfamily/defender/default.mspx]
Dr. Web Cureit - [http://www.freedrweb.com/cureit/ freedrweb.com/cureit]
If these don't find it or can't clear it, please tell me and I'll provide you with further assistance.