CautionHKLM\SYSTEM\CurrentControlSet\Services\Sermouse\Parameters
| Data type | Range | Default value |
|---|---|---|
| REG_DWORD | 0x1 - 0xFFFFFFFF | 0x2 |
In Windows NT 4.0 and earlier, this entry stored the number of buttons on the serial mouse that were detected at startup. In Windows 2000, the number of mouse buttons is stored in the device-specific subkeys of the Enum subkey (HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum) subkey. However, the system still uses the value of this entry as source data.
If you have a serial mouse, and have upgraded from Windows NT 4.0 and earlier, the system copies the value of this entry to the device-specific Enum subkeys of all serial mouse devices and uses the value in those subkeys.
Caution
The value of this entry is copied to the device-specific Enum subkeys of all serial mouse devices recognized by the system. If you change the value of this entry, the new value is used for all new serial mouse devices the system recognizes.