Hi GauravaRai,
Thank you for posting the question on Microsoft Community forums.
It looks like you are getting a blue screen error and unable to boot the computer to safe mode or normal mode. Is that correct?
1. Are you able to boot to normal mode?
2. Are you able to make a note of error code/message from the blue screen?
3. Are you aware of making any changes to the computer prior to the issue?
4. Do you have Windows 7 installation DVD with you?
5. What are the steps that you have tried to resolve this issue?
Blue screen error is mostly related to driver issue. However, it could also be caused by either a software problem or a hardware problem.
Try the steps given in this link and see if it helps you:
Resolving stop (blue screen) errors in Windows 7
Note: While performing chkdsk on the hard drive if any bad sectors are found on the hard drive when chkdsk tries to repair that sector if any data available on that might be lost.
You can upload your minidump files to Skydrive. Refer the link below to do the same:
Use SkyDrive to upload collected files and post screen shot/picture
Provide more information regarding the issue so that we could help you further.