The latest updates to 10.04 cause problems with online activities. Thunderbird, Firefox, and Opera are all affected. There are probably more. You have two options at this point. First, you can upgrade to 12.04. That should be an option in update manager. Or, you can roll back the update and continue with the previous version. Both have a couple of drawbacks. Upgrading to 12.04 (or higher) may slow down older hardware. It did in my case. Remaining with the previous version will prevent any future updates.
If you wish to roll back to the point prior to the latest updates, install Grub Customizer and move the previous version to the top of the list. The first version listed (you'll want the one that lists 60 as the first one) is the one that boots automatically. You can find more on Grub Customizer here http://launchpad.net/~danielrichter2...rub-customizer
Other posts on this subject can be found here.