How can I block ads on Firefox? (Windows 7)?

[David]

Select 'Add-ons' from your 'Tools' bar at the top of you FF browser. Click on 'Get Add-ons' then search (top-right of screen) for 'Adblock Plus'.

Install it (I believe there are different versions of it now - choose which best suits you - or all if them if you like). Once enabled this excellent little pop-upblocker and should solve all your problems.

Note: You should download and install a great little utility called 'CCleaner (formerly 'CrapCleaner').
It will clean your whole system up no problem, removing all traces of these annoying pop-ups which sometimes attach themselves to your system and are hard to get rid of.

Hope This helps