The "proper" way to update firefox is to go to Help>About Firefox - this will automatically check for an upgrade and automatically download and install it. You don't have to do anything except click "apply update" if one is found.
If you have to download it, go to http://mozilla.org and nowhere else. If you get it from some download website they can bundle it with spyware and more. This is probably your issue, there is other things installed on your system that you are not aware of that is causing you problems.
Anyways, glad you are fixed
1. something that is contemplated, devised, or planned; plan; scheme.
2. a large or major undertaking, especially one involving considerable money, personnel, and equipment.
3. a specific task of investigation, especially in scholarship.
4. to propose, contemplate, or plan.
5. to throw, cast, or impel forward or onward.
6. to set forth or calculate (some future thing).
7. to extend or protrude beyond something else.
8. to use one's voice forcefully enough to be heard at a distance, as in a theater.
9. to produce a clear impression of one's thoughts, personality, role, etc.