recursive queries first parant then all child + child of child .. etc

hi,i want to diplayfirst the parant and then all it's subsequent children at differentlevel, then second parant and all it's subsequent children , parentelements is null with levelid=1 i am using sql server 2000,and i don;twant to pass any root elemenet id, it should bring from start to end.
input
id name parentid levelid
1 a NULL 1
2 b 1 2
3 c 1 2
4 d 2 3
5 e 4 2
6 f NULL 1
7 g 6 2
8 h 7 3

i want the output like this

id name parentid levelid
1 a NULL 1
2 b 1 2
3 d 2 3
4 c 1 2
5 e 4 2
6 f NULL 1
7 g 6 2
8 h 7 3