Windows 7 Crashed and Blue Screen Problem

[technoankur]

Last night my laptop shuts down because of low battery and after plugging the AC Supply when i restarted the Windows 7,it din't worked.
It asked me for the two options - Startup repair and Launch Normally.I chose Launch Normally but after 3 seconds of the boot screen,there came a blue screen which just flashed for half second and laptop got restarted.

This is happening again and again.Someone please tell me a way to get out of it.I don't want to loose windows as it has very very important data for me

 

[Vir Gnarus]

During startup, constantly press the F8 key to bring up the boot menu, which you can then select Safe Mode with Networking. If that does not work (if it BSODs) then try regular Safe Mode. From there you can provide us information as mentioned here.