The others have made some excellent suggestions. All a worth a try. My only suggestion is similar to what the others have suggested. Try to see if you can get your hands on a Windows 7 Install Disk. Then try to boot from it and if you can choose Recovery Console. Once there run Chkdsk on the hard drive to see if all system files are good. If you cannot get a Windows 7 Disk then what the others have suggested is to run a diagnostic on the hard drive using the manufacturer diagnostic software. Of course you will need access to another working computer and internet access unless of course there is diagnostic software and or Windows 7 installation files on another partition.
Also I have noticed an issue with HP laptops and Dell laptops that present a black screen and the only option is to power down the computer. The BIOS needed updating on both cases. If you can check the manufacturer's site to see if there is an update then I would suggest you download it on another computer and update the BIOS. Of course you need to access the internet on a working computer. On desktop machines you can check the BIOS version on startup
Here is a link that shows you how to check the existing BIOS version on your computer. Hopefully one of the options will apply to you.
How to find BIOS version on computer
Hope that helps