entered into the Registry, permissions allowing. They can be changed indirectly by using Group Policy, applied locally to a single computer with or to a domain with . It may be necessary to either logout or restart the computer in order for any Registry changes to take effect. Evaluation order The and Registry entries can exist in two places, the per-user setting (under HKEY_CURRENT_USER) and the per-machine setting (under HKEY_LOCAL_MACHINE). If an entry appears under HKEY_LOCAL_MACHINE, then any corresponding entry under HKEY_CURRENT_USER is completely ignored. The data values are not merged in any way. When deciding whether to activate AutoRun, both and Registry entries are consulted. If either value indicates a drive should be disabled then AutoRun is disabled for that drive. Thus in the following example: the data value taken for is 0x08, disabling drive D and the data value taken for is 0x95, disabling removable and network drives. The per-user entry is never used. NoDriveTypeAutoRun This Registry entry disables or enables the AutoRun feature on all drives of the type specified. It reflects the setting of the relevant Autoplay Group Policy. Valid data ranges from 0x00 to 0xFF in hexadecimal notation. If the entry is not present, the default data value is either 0x95 or 0x91 depending on the version of Windows used. An entry present in HKLM overrides any entry present in HKCU. The entry data is a bitmapped value, where a bit set to 1 disables AutoRun on a particular type of drive. The bit settings for each type of drive are shown below: Note that bit number 1 is unused and that the "Unknown" type is represented twice. Setting all bits to 1 would give a hexadecimal value of 0xFF, decimal 255, and would disable AutoRun on all types of drives. The default setting for this entry depends on the version of Windows being used: NoDriveAutoRun This Registry entry disables or enables the AutoRun feature on individual drives. It is not associated with a Group Policy and does not exist by default. The data value is taken to be 0 if the entry is not present. An entry present in HKLM overrides any entry present in HKCU. The data is a 32 bit (DWORD) bitmapped value, of which the lower 26 bits are used to represent each of the 26 drive letters from A to Z. Thus the valid data range is from 0x0 to