Go to Start > Programs > ArcGIS > License Manager> License Manager Tools and choose the Service/License file tab.
Select 'Configuration using Services'. Click on the 'ESRI License Manager' service to select it.
Click on the Utilities tab.
Click the Perform Check Sum button.
NOTE: This function will only return information for the FIRST .lic file in your C:\Program Files\ESRI\License location. (ex. ArcInfo.lic) You will NOT see checksums for every license feature you have. If you wish to see a status of these features, please use the Server Status option.