Black screen after boot, Stuck Windows setup

My laptop runs Windows 7 HP 64-bit.

HOW THE PROBLEM STARTED:
I was trying to repair install the OS from setup from my hard disk. When I returned after two hours, there was a black screen, and system was non-responsive. I waited for another half an hour, but decided to restart the laptop.


Since then there were two options in the boot menu:
1.Windows 7 2.Windows Setup Rollback

Either of them lead to the same black screen(even the backlight is off) after the windows logo.The black screen stays indefinitely long until I repeatedly press Esc/CtrlAltDel/CtrlShiftEsc, which causes reboot after some time

when I selected Windows 7 option and ran in Safe mode, a low res setup screen saying that
"Windows cannot complete the installation in safe mode. to continue installing windows, restart the computer"
appears and then the system restarts

Then tried repairing the OS from Command Prompt in the repair options. I tried bootrec, of which FixMbr and FixBoot ran successfully, but ScanOS and FixMbr showed 0 windows installations.

Since this step, the "Windows Setup Rollback" Option has disappeared from the Boot menu, but the back screen after booting and the "setup cannot continue..." screen still appears in safe mode.

Startup repair can't detect any problem
sfc /scannow says that there is a system repair pending, restart and try again
No memory hardware errors

Note:I cannot format the disk as a lot of important data is in the same partition as windows.

How am I supposed to repair the Windows without affecting the settings and my personal data?

At least tell me how to abort this stuck installation to get back to the (corrupt but most of the stuff still working) state before the installation started(urgent, need it for studies )

Thank You

I have no drive large enough to store the data, also I will have to reinstall all the softwares