Modifying the log on properties for a service is common when the service requires network resources (i.e.. a shared folder). In which case the service must run under and account that has access rights to the network resource.

1. From the Start Menu –> Run, then type “compmgmt.msc”
2. Expand Services and Applications and Click on Services
   
3. Right click the Service you want to modify and select properties
   
4. Select Log On tab.
5. Select the “This Account” option then change the user information and password
   
6. Click “Apply” then Click “OK”
7. You will need to restart the service before the changes take effect.