What is the model number of the laptop? We need that to provide more detailed help.
Try booting into the bios and see if the hard drive is still detected. When you first turn on the laptop, there should be a prompt (lower left or upper right) on how to enter the bios (should be F2 or F12 for a Toshiba). If you need more time, press the pause key during boot.
If the hard drive is still there, you need to run some test utility to see if the hard drive is damaged. If the hard drive is in good condition, it is most likely some damaged files that is causing this problem.