Not sure where to start. I tried upgrading to Firefox version 4.0 and I then couldn't get internet access at all. At around the same time I tried to install Kaspersky security. The installation failed because of conflicting security software (this laptop is second hand and had previously had Norton). I did an uninstall on the Norton and Kaspersky still failed. I googled and found that uninstalling Norton is a known problem, found a page that described how to completely get rid of it (registry editing etc), did all that and nothing's changed. Still can't upgrade Firefox beyond 3.6.16, Chrome no longer works, neither does IE. Pretty sure it's the Norton that's screwing things up but no idea what to do! Help!!!! :-)