Since installing 10.10, my Dell Inspiron was able to suspend both when I closed the lid or chose to suspend from the menu. At least it was until yesterday. Now if I close the lid the computer freezes. If I open the lid, the screen is black and will remain black until I force shut-down the computer. Trying to suspend from the menu also does not work, the screen goes black and the system freezes. A bit of googling brought up a bug that might be a possible cause? https://bugs.launchpad.net/ubuntu/+source/linux/+bug/522998
It says: "When the XHCI module is loaded the system cannot suspend.
Manually unloading XHCI will allow suspend to complete normally.
If SUSPEND_MODULES="xhci" is added to /etc/pm/config.d/unload_module then the system can suspend normally.
Looking in /etc/pm/config.d/ I see an empty dir. Does anyone know if this could be a solution, how to implement it if it is (make a new file unload_module and add the line in question?), and, if not, other ideas on where to go, or hardware tests to run?