How to script a field of buttons to Fill login boxes?

Hi,

I am a IT Systems Coordinator and unfortunately have about a half a million password to remember for all our different systems.

I used to work for Shell where we had a little bit of home made software where there was a box with about 10 buttons and behind the buttons multiple options ie:

Username:
Password
Domain (or any other 3rd box)

I wanted to recreate this but can think of a nice and easy platform to start of with.
I have some experience in VB, C++, PHP etc.

But cant really think of the easiest startup.

Can anyone give me an idea of where to go with this?

Thanks