Short DST passed but Laptop(Dell Inspiron n5010) hangs at Starting Windows screen.

I have Dell Inspiron n5010. I purchased it 3 years back. Now when I press the power button it starts and HANGS UP at 'Starting Windows' Screen. I tried to run it in Safe Mode, in Command Mode and with Networking too but nothing helps. I am stuck with it. I even tried Memory Test in Boot options, it says Memory Test pass. I even tried to repair the windows but guess what? it failed to recover and no restore point is being shown. Unable to do project work. Laptop isn't starting at all.
OS: Windows 7(Ultimate) 32 bit.
Windows is genuine.
