Every time I click on an email address in Windows 7, it starts opening up new tabs and won’t quit. How can I fix this?
Firefox keeps opening many tabs or windows
Managing file types
Check the mailto protocol, it can't be set to Firefox.
Clicking on an email address doesn't open tabs in a browser, so it's not clear exactly what you're referring to. Email links will launch your default email client and open a new message with that email address filled in, but that has nothing to do with your browser.
You need to be much more clear as to what you're doing when this happens, and exactly what you see when it does.
Of course it is possible that your browser (Firefox, I presume) has a preference set incorrectly, which definitely could cause this behavior.
Check the Mailto application in Firefox ->
Preferences -> Applications and make sure that it's set to your default Mail application, not Firefox.