dvd runs and freezes

[c]

I just up graded to xp home to get away from ME
problems. After intall--got message to upgrade dvd
decoder--so i spent $ on line to do this because my
dvd/cdr/w would just start running--all by themselves
with nothing inside and the computer would freeze. So I
did the up grade for windvd. The problem still exists,
but not as much. I use control/alt/delete and sometimes
it will stop or I open the cd door and then wait. What
tiggers the cd/dvd to start? Also, I have re-installed
xp to see if that would help.
Any suggestions?