Hola que tal:
Necesitas declarar dos funciones API externas:
FUNCTION long GetComputerNameA(ref string ComputerName, ref ulong BufferLength) LIBRARY "KERNEL32.DLL"
FUNCTION long GetUserNameA(ref string UserName, ref ulong BufferLength) LIBRARY "ADVAPI32.DLL"
Entonces:
long ll_ret
string ls_ComputerName, ls_UserName
ulong BufferLength = 250
ls_ComputerName = Space(BufferLength)
ls_UserName = Space(BufferLength)
ll_ret = GetComputerNameA(ls_ComputerName, BufferLength)
ll_ret = GetuserNameA(ls_UserName, BufferLength
Un Saludo y suerte!