Skype shouldn't be affected by the version of Firefox you have installed. You don't need a Skype extension in Firefox to be able to use Skype.

Thank you, do you have any idea what it can be then?

I'm sorry the-edmeister but I did not find your comment shed light on my problem. I definitely cannot open skype, nor can I open any attachments in hotmail, nor can I do anything with winzip, and I think it has affected my kaspersky. When I transferred to the latest firefox version it did bring up a pop up box in which it asked if I wanted to enable winzip, skype, and kaspersky security. I naturally clicked 'yes' and hit return. After doing so the next message said that these three things were disabled and would be enabled when they became compatible. Very very frustrating. Anyone have any ideas what is going on?

I had the same type of failure. It was caused by a FF upgrade from V4 to V9.1. There are no extentions added at this time. My USB ports also started acting up. I could not re-install the Webcam that was installed before. Lifecam application said the camera was not detected. The computer gives an audible "Hardware Connected/disconnected when the cameera is plugged and unplugged. The HP Scanner of my OJ 8500 stopped working (USB). Did get it to work via Wireless. Removing FF did not clear the problem. Believe I have infected USB driver now.

Another indication is AOL Desktop 9.6 has started to display an Error box, with OK in the middle (Nothing else) and the Closing X om the corner. Clicking on the Close up to 4 times will finally clear and AOL Desktop becomes somewhat functional. The commonality, as I see it, is USB ports, Skype & Webcamera.

An Experiment: I had a computer with a V3.x FF installed and Skype. I made a Skype call and it worked. I went to FF / Help / About to check the version. At the top of the About display I saw that FF was upgrading to 9.1. I left it alone to see what would happen. Well, it installed 9.1. It opened to make some settings but nothing about Skype. When I could close FF 9.1, I did. I went to Skype and tried it and got the failure others had reported to me. The solution was th get the new upgrade of Skype. I had the latest so that was not a viable option. I removed FF 9.1, Rebooted and everything went back to normal. Skype worked without a hitch. Total test time was less than 30 minutes and I opened nothing else. This may be why I did not experience the problem of my customer which I reported above, the Printer, USB & Webcam problems.