I have a Dell Inspiron(N5010) laptop which has an I5 processor. My system had a genuine Windows 7 (Ultimate edition)[Plus Ubuntu installed]. It also has 4 GB of RAM. I am facing troubles while starting the Windows. Now let me explain the scenario-
A few days back, while working on my laptop, I closed the lid of my laptop and accidently felt asleep. When I opened the laptop, it gave me some trouble while starting up. It started shutting down abruptly. Luckily, I chose to open my laptop in Safe Mode and able to retrieve the system to a not-so-old state. Though, I had Dual Boot - Windows and Ubuntu. But after restoring my system, I am unable to get the option of choosing Ubuntu. So whenever I started my system I would get 'Starting Windows' screen. But else while, there were hardly any data loss issue.But the real trouble was to follow.
Two days later, a friend of mine took my laptop and after using it, he chose to Hibernate the system(cause I used to frequently put my system to Hibernate and this had been working fine for me). But soon after putting the system to Hibernate- he closed the lid/flap of the laptop(probably Hibernate did not get completed). Next morning when I tried to start my laptop, it booted fine(instead of Resuming Windows- it booted as if it had been properly shut down the previous time). Soon after opening my user account, the system shuts down abruptly. I tried to start the laptop again, and this time, after the 'Starting Windows' screen, it abruptly shuts down. There is no power issue at all because I had the charger on and even if the system doesn't has sufficient battery- it displays a warning message before the boot begins. I tried again and the same result. Then I tried to Safe Boot my system(because this had worked a couple of days back) - but soon after reaching the user account screen- it produces the same result. THEN, I went to the boot menu, and within seconds, it shuts down again. I put the system away for a while. Now I tried to open it again. This time, after pressing the power on button, I repeatedly pressed F8 key, and choose 'System Repair'. After that, the system reaches a screen where I had to choose the user account. I chose my user account rather than the Administrator. After having entered the credentials, it shuts down again. This has been quite a frustrating incident. I have some enormous amount of Data with me, with High critical value. I am afraid, I could loose all- which could even have monetary impact also. AFTER some hours, I tried again. This time, it boots normally, and after the 'Starting Windows' screen, I am prompted of a Disk Checking step. I choose to go ahead with Disk Checking. But after having done 7-8% checking, it fails in the same manner yet manner. I tried once in for all, for the last time, this time again I proceeded with Disk Checking. This time, it does something more than 20% checking, before shutting down abruptly.
What could be the issues? How can I repair my Windows- without loosing my data and the softwares installed. What is causing the issue? Is the problem Hardware related, or Software related or both? Has my Windows crashed?
Update: My system has some over-heating issues as well. But all these incidents have started happening only recently. It is almost 4.5 years old, but until the last week, it had never ever troubled me in this way. Also, my laptop has two partitions. 'C' drive/partition had nearly 29.2 GB of free space and the other partition had around 650 MB of free storage left.