We have seen several cases of new Dell Optiplex 745 computers that will not boot after installing Symantec AntiVirus 10.1. The computers begin to boot and then hang at a black screen. Safe Mode works but you cannot boot normally.

This is a known problem with Symantec. The following resolution has been successful in our our testing (You will have to create registry key):

See the original Symantec Article

To create the UseVolumeInfoList registry value

1. Boot the computer in Safe Mode
2. On the Windows taskbar, click Start > Run.
3. In the Open box, type the following text:
   
   regedit 
    
4. Click OK.
5. In the Windows Registry Editor, in the left pane, go to the following key:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Intel\LANDesk\VirusProtect6\CurrentVersion\Storages\Filesystem\RealTimeScan 
    
6. Right-click the RealTimeScan key, and then click New > DWORD Value.
7. Type UseVolumeInfoList for the value's name, and then press Enter.
8. In the right pane, double click the UseVolumeInfoList value.
9. In the Value data box, type 0
10. Click OK.
11. Restart the computer.