I had Mozilla Firefox installed in my Acer laptop. I have Windows XP3 OS. For the last few months, Firefox used to freeze suddenly after working for 15-20 mins. I then used to close firefox and then tried to restart it. However, a message used to pop up "Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system." I used to press Ctrl+Alt+Del and used to select firefox.exe and click on End Process. Even after that Firefox will not restart. I had to restart my laptop. I uninstalled and installed Mozilla several times and then changed to Google Chrome. But now I find Google is also freezing after working for some time. I have QuickHeal Antivirus installed in my laptop since the last 6 years and generally do not open more than 3 to 4 tabs at a time. I do not use WiFi to connect to internet. Can anyone help?