Turn the laptop off completely. Try to restart it and when you push the "start" button, immediately push and hold F11. If you can get it to show you options, open in "Safe Mode" and try a System Restore.

From Safe Mode, the sequentce is: icon in lower left corner>all programs>Accessories>System Tools>System Restore. Pick a date back a week or so.

Unfortunately, the fact that you mention the HD only spins for a few moments leads me to think it may be a hardware problem.

Rich