Goto Control Panel > System and Security > Windows Update > Check for updates or click n number of updates are available link.
Windows users will see the Windows 7 Service Pack 1 listed in the important updates list
Windows 7 Service Pack 1 for x64-based Systems (KB976932)
Windows 7 Service Pack 1 is at recommended collection of updates and improvements to Windows that are combined into a single installable update. The service pack can help make your computer safer and more reliable. A typical installation will take about 30 minutes to complete, and you will have to restart your computer about halfway through the process.
If the issue is still not fixed, it can be a very critical problem with your computer affecting your personal data and the Windows Operating System. You will have to chat with our Experts or you can check with your local technician to get the problems fixed with very high priority.