Hi Mansha,
Welcome to Microsoft Community. I understand that you are getting dialog box stating S Agent restarting every time you switch on your computer.
Samsung S Agent is a software application that is generally pre-installed with various Samsung laptop models that is designed to keep veracious bundled software on the PC up to date. It runs as a Windows Schedule Task called SAgent that is designed to run when the PC boots. This task will run in the background and periodically check for and update various programs on the PC and may do so without the users direct visual knowledge.
If you want to uninstall it please follow the steps below.
1)Press Windows and x key to open a task list from the bottom left corner of the screen.
- Select **Control Panel.**3) Select Programs and Features.
- Double click on the program you want to uninstall and follow the onscreen instructions
If you wish to install software again you can refer follow link to download and install.
http://www.samsung.com/uk/support/category/pcperipheralsprinter/notebooknetbook/
If you need further assistance regarding Windows, please feel free to post. We will be happy to help you.
Thank you.