Adblock Plus is a Firefox add-on that makes ads disappear (and has plenty of other useful features, too).
Just install the tool, restart Firefox and it'll begin filtering your web pages immediately. Most, if not all of those annoying Flash ads will disappear right away, speeding up your browsing and allowing you to concentrate on the site content.
The program hasn't worked for you? Adblock Plus provides a choice of more than 40 filters, and you can choose the ones that are most effective for you.
There are filters for many languages beyond just English, for instance, from Dutch, French and German, to Chinese, Vietnamese, Japanese, and more.
And you can also install filters for many specific purposes: to block ads on adult or P2P websites, to protect you from privacy risks, keep you safe from known malware domains, and even a blacklist for known Rickrolling pages (no, really...).
What's new in 3.5 (see Release Notes for more):
- Overall CPU usage is down by ~60% since the last release
- The $rewrite filter option can now take a value of the format abp-resource:<name> where <name> is the name of a built-in resource
- If there are multiple filters with the $csp option that match a URL, now all corresponding CSPheaders are injected into the document
- Added a new Korean filter list
- Fixed: Domain-based whitelisting did not work in data: URI frames
- Fixed: Element collapsing style sheets could linger after the frame was destroyed
- Fixed: Critical notification animation did not stop when dismissed