Delphi quickie: Detect Windows version, amount of RAM and installed service pack

Implement the following: Procedure DetectWindowsVersion(var Windows : String; var ServicePack : String; var RAM : String); The Windows parameter would be used to return the version of Windows, and the ServicePack parameter would be used to detect any installed service packs and the RAM parameter would return the amount of installed memory (RAM) in GB. Running DetectWindowsVersion could return for example Windows="Windows 7 Ultimate", ServicePack="SP1" and RAM="8.0", or Windows"="Windows 2000 Professional" and ServicePack="SP3" and RAM="2.0". If no Service Pack is installed, then ServicePack="". The function must work in Windows 2000, XP, Vista, 7 and 8 and support all the currently available service packs for these operating systems. Note: The RAM detection must detect RAM sizes over 4 GB.