This features in Windows 7 let you find the history of error encountered in your PC. Once the error encountered is fixed you can delete the log from your PC. Windows Security Center also continually monitors these security settings, and informs the user via a pop-up notification balloon if there is a problem. It is renamed to Action Center in Windows 7, where it covers maintenance as well as security.

Follow following steps to find one in your PC.

Steps I - You can access Action centre through task bar notification balloon or through Control Panel.

To Access through taskbar notification

Click on notification balloon on your task bar as marked below

 And than click on Open Action Center as marked below

To Access through Control Panel

Go to your Control Panel and click on Action Center as shown below

Step II -  Once you are in Action Center, Click on drop down arrow on maintenance to get more options as shown below.

Step III - Click on View reliability history as shown below

Step IV - Click on view all problems report as shown below

Step V - Now you are on problem reports page, you can go through it to see what's problem your PC has encountered. You can delete or save the report.