Charity membership drive – using a laptop as a signup form

You could use a webform for this — if your organization has anybody with even basic PHP experience, you could set it all up as a webform which just appends the data to a CSV. Internet Explorer on Windows 2000 and later can be locked down pretty tightly using Group Policies. You can set IE to be the only program running, disable closing it, and remove any links to other pages then disable the address bar. You could also use the R-Kiosk addon for Mozilla Firefox - it puts the browser into "kiosk mode", where it's full screen, you can't exit, and I believe it has ways to specify which sites can be visited and which can't. If you'd like more info on either of those options, let me know and I can give you some pointers.