You have a good video card in that laptop.. do you have the proprietary nvidia Drivers installed ? they do NOT get installed by default because they are not free drivers..
You must have non-free repositories enabled in your sources list for the following to work.
CTRL + AL + F2
- to get to a command prompt
Log in as root
aptitude install module-assistant build-essential
m-a a-i nvidia-kernel
aptitude install nvidia-glx
When the reconfiguartion script with that last command,
as the driver
then restart the X server
That should fix your video playback issues.
If an update breaks your graphics in the future, just repeat the procedure starting with m-a update, and skipping the dpkg-reconfigure steps because the configuration is already done.