WSUS & .net Framework in Windows 2000 Environment

Today, I installed WSUS in Windows 2000 environment for a client, the result is bush. The trouble is on .net Framwork.

.net Framework is required when you install WSUS in Windows 2000 environment. The installation guide of WSUS has stated that .net Framework 1.1 with SP1 is required. I downloaded .net Framework 2.0 and installed it. Then I get a error message when I installed WSUS, the message stated that .net Framework 1.1 with SP1 or above is required. Please pay attention on ABOVE, I don't even want to say something more.

Of course, the problem may not lie here. Maybe the reason is I uncompressed the setup package of WSUS. Before I go to client work site tomorrow and test again, I don't know the specific reasons.