It sounds like you have the appropriate info from the rest of the crew,
especially if you are able to get support from HP, but it sound like the
sort of thing that happens when you update the kernel and are using the
ATI Proprietary Driver. The ATI driver needs to be uninstalled and
reinstalled each time you update the kernel. You can confirm you are
using it by looking at your xorg.conf
-If this is the case- you can still recoup your system... go to ATI's
site and download the Linux driver appropriate for your system, then
install it. You may run into problems as it wants -you- to manually
uninstall the old driver first - yuck! - so get in the habit of KEEPING
the installation file so you can do that easily next time. Uninstall
using corresponding file, then re-install using the new one, and so on.
You can also force the install - and that will work, but not as clean.
Of course, if you are already getting appropriate support from HP, or
are not using the ATI driver, then please let them help you and ignore
my advice. ;-)