I have a laptop running Windows 7 I believe. I cannot seem to upgrade this laptop from Version 15 - I get the notification that a new version is available but it will not work. Many times I will try to bring up Firefox and get an error as if it doesn't exist - if I try to install any other version, I get the same error after it says it successfully installed. If I reinstall 15 it works. Problem is that several sites say they don't work best in the older version and I need to upgrade. Please provide me with some assistance. I have another laptop that is fine as well as various pc's I work with a home and in my office. I am very tech savvy and am not afraid of upgrading, etc. on a computer. Thank you.