Please check here to see whether your email setting can be easily restored:

orange Firefox button or Tools menu > Options > Applications

In the search box, type mail and pause until mailto appears. If you review the choices in the drop-down list, can you find the mail program or webmail site you want, and if so, does it work again?

Hi and thank you for your reply. Unfortunately I tried that a few days ago and I no longer had the "gmail" option which is what I use. It gave me outlook and hotmail/live something. Thank you.

That's strange. You might try resetting download actions as mentioned in this thread: the mailto feature was set to gmail one day and the next day Firefox says there is no application set as my mail handler. | Firefox Support Forum | Firefox Help.