Hi Ka,
Thank you for posting your query in Microsoft Community.
Let me ask you:
- Did the problem start recently?
- Is the problem occurring randomly or does it only happen while performing a specific task?
I would suggest you to follow the methods below and check if it helps.
**Method 1:**If it is recent problem try to perform a system restore and check.
http://windows.microsoft.com/en-us/windows7/What-is-System-Restore
**Method 2:**Verify below services are started, in order:
Press Windows key + R, type services.msc and click OK
DCOM Server Process Launcher
RPC Endpoint Mapper
Remote Procedure Call (RPC)
Security Accounts Manager
Server
If they are not started, start them and check. To start services, double click each of the services and start them if they are not started.
Hope this information is helpful. Please feel free to reply in case you face any other issues with Windows in future.