Using flash , features: memory and play video

(flash cs3 pro, action script 2.0, win xp)

i want to use flash to make a test application. it should have

buttons, which should direct to another screen when pressed, and

checkboxes that can be checked. i am quite new to flash cs pro, i

managed to switch from screen A to screen B, and back from screen B to
screen A.

but the problem is, i want to make lots of checkboxes on
screen A. An user should be able to check any of these. And if they
are checked, they should remain checked, even when the user switches
to another screen. so when the user switches back to screen A with the
checkboxes, they should still be checked. So somehow the state of the
checkboxes should be stored and retrieved again? Could you explain how
to do this to a beginner flash user?

another feature that has to be included are is a video screen. a .avi
file should play when a button is pressed, and the video should run
and always keep running (so no pause or stop) even when the user
switches to another screen. it a sort of monitoring app so the video
should still run when the user switches back to the videoscreen.