As I start it it hangs in few seconds.what can I do

Once is has booted up, right click the start button and select command prompt, powershell or terminal - depends on which version of windows u r using.

Select the admin option or open as admin. Type CHKDSK C: then hit enter. This will check your HDD for errors and if there are it will tell you there are.

If it says it found errors, then type CHKDSK C: /F and hit enter. You will have to reboot for it to run.

You can just do the latter, but I like to know if that was as problem and the latter just fixes the problems it finds and does not tell you if there were any.

If there are serious or many errors, it may take a long time for it to finish. Just wait till it is done. If it does take a long time, you might want to consider replacing your HDD as it could be a sign of a degraded drive. At a minimum, insure you have a current backup of your files. Use a utility to check the S.M.A.R.T. data. That will tell you how bad it might be.

When it is done, type SFC /SCANNOW, then enter. This will also take a while to finish. It tests the system files and replaces any that it finds corrupt.

If problems are found that could not be fixed, insure you are online and enter dism /online /cleanup-image /restorehealth

Once done, verify normal operation.

I HIGHLY recommend downloading a copy of Macrium Reflect Free - it is no longer supported but is available.

Create an image of your HDD and a USB restore drive.

It is VERY simple to do with this program. Once you have that, u can restore a corrupt system or transfer your system to another HDD/SSD very easily without the need to reinstall all your programs.