I'm on Vista and I'm trying to install v2.8.3 and I am running it as administrator. When the dialog box pops up saying it's preparing to install, another box pops up saying the wizard was interrupted and it failed to install.
How am I supposed to fix that?
I'd suggest re-downloading the 2.8.3 using a download manager like DAP. This will avoid any corrupt or incomplete downloads which are the most common cause of your problem above.