Just download Firefox. If it work, post and I will show you how to set it up so that is the one that you always use.
You can also try to repair Word http://office.microsoft.com/en-us/wo...010357402.aspx
I doubt if a repair will work, however.
The very best advice that I can give you about the computer is not to do anything unless you feel confident. The advice that I gave is very simple and you may be able to get a friend to help. Its something so easy, you only have to give a thank you to your helper and nothing more.