Hi Niraula,
Thank you for the detailed information.
1. Are you using IObit Malware Fighter application?
This issue is because of application running in the startup, a particular file is missing/corrupt of the application.
Clean boot helps you to find the issues casing application, you can uninstall and reinstall application to fix the issue.
Keep the computer on a clean boot and check. If everything works fine after a clean boot, you can infer that some third party services are causing the issue. Proceed with the remaining steps to pin-point out the third party service. After you figure out the issue causing program, you may have to update or install a latest version of the program.
How to perform a clean boot to troubleshoot a problem in Windows Vista, Windows 7, or Windows 8.
http://support.microsoft.com/kb/929135
Note: Please go through the section: “How to reset the computer to start as usual after troubleshooting with clean boot” of the Kb article to boot the computer in normal startup after fixing the issue.
Hope this information helps you. Please do let us know if you need further assistance, we’ll be glad to assist you.