If that fails, try tapping F8 at startup to enter Advanced Boot Options
look for Repair My Computer
which when selected gives you System Recovery Options
Try running Startup Repair repeatedly from there. If it fails, try System Restore progressively backwards until it starts.
If these fail, open the options Command line to run SFC -SCANNOW Run in Command Prompt at Boot
Next try all of these repairs using the Windows 7 DVD Repair console or System Repair Disc - Create
so repairs are not reliant on possibly corrupt System Files.
If these fail you should consult your parents and let them in on the help you are getting here before proceeding. Next copy out your files using this method: Copy & Paste - in Windows Recovery Console
or using Paragon free Rescue CD.
If you'll let us know the make/model of your computer, we can give you the exact steps to run full Factory Recovery at boot, or using Recovery Disks if you have them.