I was wondering if its possible to to set up a computer where a user can only use the web browser and nothing else? they won't have access to any other part of the computer and they won't be able to see any other part of the computer. I was wondering if its possible to setup a computer (windows, mac, linux) and have everything else blocked and locked so that only the web browser (preferably firefox) is available. the user won't be able to minimize or close the browser and documents or files that come off the web are viewed in the browser and deleted once the user is done viewing the documents or files. The user won't be about to connect any devices like a usb, ipod, etc... This probably sounds like a stupid question, but I know it can be done and I know its been done but I just don't know how its done. What addons or plugins will I need? Will there be any scripting or programming involved?
You need to shift from Windows to Chrome OS
Google Chrome OS is a Linux-based operating system designed by Google to work primarily with web applications. The user interface takes a minimalist approach and consists almost entirely of just the Google Chrome web browser; since the operating system is aimed at users who spend most of their computer time on the Web, the only "native" applications on Chrome OS are a browser, media player and file manager.This means that Chrome OS is almost a pureweb thin client OS.
The word you are looking for is KIOSK. You want a kiosk setup where you can limit users to only certain activities although your desire is a little too limited. If you want browser only that's fine, so is external device connection. Viewing documents requires more than firefox, in linux you could go with a document viewer but I'm not sure how you could keep users from saving the files. You could have only one folder accessible to them and delete them yourself or set a cron job to do it periodically.
There are Kiosk software available for most Linux distros just google them. Another option is a lockdown but that is again too restrictive from your description.