It seems that something has happened to boot files which are needed to properly load Windows 7. Since you have Windows 7, you can fix the problem easily. First, restart your computer and then keep pressing F8 button rapidly and you should see Advanced Boot Options menu which looks like this: Once you see that menu, select Repair Your Computer option and press Enter. Wait a while and follow the on-screen instructions. You should get to the window that has several repair options, including Startup Repair, as shown on this image: So, click on Startup Repair which should fix all found startup problems.
Once it has finished, your computer should restart and operate normally. However, if it is still the same, repeat the instructions to go back to System Recovery Options window, but now select System Restore: When you click on System Restore, follow the on-screen instructions where you can choose one restore point based on a date to revert system settings back to that date (when all worked fine). Wait for the process to finish and it will automatically restart a computer. Hopefully, the problem will be gone. Don't worry about your personal files as they won't be affected by System Restore. I hope this helps! Regards, IT Miro