If you need keep your browsing private, then an Ubuntu Live CD is the answer.
The first step is to eitherburnan Ubuntu Live CD, or prepare anon-persistent Ubuntu USB flash drive.
punch parameters at the top of the Synaptic window, and then select Repositories.
Add a check in the checkbox with the label ending in “multiverse”.
hit the Reload button in the main Synaptic window.
The list of available packages will reload.
When they’ve reloaded, jot down “restricted” in the Quick search box.
Right-hit ubuntu-restricted-extras and select Mark for Installation.
It will note a number of other packages that will be installed.
Click Mark to accept the installation of these other packages.
If you open up Firefox now, you’ll have no problems using websites that use Flash.