To make the files in the data and conf directory writable you need to give “Write” access to the Internet Guest Account
(IUSR_computername) or the appropriate web server group (like IIS_WPG). This is done through the right-click context menu on folders and files chosing “Properties” and selecting the “security” tab.
Upgrade packages are zipped in a .tgz format so you can download 7zip to unzip it.