2007 Macbook shows black screen and cursor when woken from sleep. What should I do?
I've had this happen too.  Solutions that occasionally work:


Close the lid, wait for the 'sleeping' light pulses from the front of the laptop, then reopen and try again.
Type my password (I have password protected sleep/screensaver) and hit enter blind.
Wait a few minutes
Sleep the computer by hitting the power button once (not holding it down), then waking it up.
Swearing profusely


Solutions that almost always work:


Force rebooting.