A full format means it erases everything and re-installs the operation systems, You can use the feature that allows you to take your computer back to the last known good configuration, which would be better. format only as a last measure. Do a search on your computer for system restore. Windows 7 has help files which can help you better understand what they are and what they do. This may help you resolve a lot of issues. Also look in control panel for add and remove programs, make sure you don't have multiple versions of the browsers, if so click remove. Help files can help you with that as well. Another good option is, google each of these options, there's a lot of help online to help you learn about these things. Good luck. Send me a message on my profile if you have any other question, I'll try and answer your questions to see if it helps.
Jonathan