Reinstallation of DivX on a new machine

Hello
For several years, I used a computer with Windows XP
I installed DivX Player (don't remember what I did exactly !), bought some DIVX sequences (filaes *.divx) and played them. Everything worked fine
Recently, I bought a new computer with Windows 7 - 64 bits, installed Divx (very basic installation) and transferred all my *.divx (and even AVI, MPEG ...) files
When I try to play them, I get a "scrambled" screen inside DivX Player
Did I forget something ?
Is there a codec problem ?
Thanks to everyone who could help ... and to the others too !