Click Start, type msconfig in the Start Search box, and then press ENTER.
If you are prompted for an administrator password or for a confirmation, type the password, or click Continue.
2. On the General tab, click Selective Startup.
3. Under Selective Startup, click to clear the Load Startup Items check box.
4. Click the Services tab, click to select the Hide All Microsoft Services check box, and then click Disable All.
5. Click OK.
6. When you are prompted, click Restart.
7. After the computer starts, check if the issue is fixed.
If your issue is resolved after performing Clean Boot, then follow the steps mentioned in the following KB article to narrow down the exact source: How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7
If you can isolate one service that is selected when the problem occurs, that service is the one that causes the problem