Find Service Pack installed in Windows server

To find out the service pack installed in windows server 2008 R2, we can query the registry as follows:

 

Hive: HKEY_LOCAL_MACHINE
Key: system\CurrentControlSet\control\windows
Name:CSDVersion
Type: REG_DWORD

The name is CSDVersion and here should be the value as per service pack installed:

Value: 0x100 SP1
Value: 0x200 SP2
Value: 0x300 SP3
Value: 0x400 SP4
Value: 0x500 SP5
Value: 0x600 SP6