Found out you can’t install SQL 2k8 while a .NET 4 reboot is pending.

SQL hangs with…

Process 0:0:0 (0x41c) Worker 0x049100D8 appears to be non-yielding on Scheduler 0. Thread creation time: 12973098587813. Approx Thread CPU Used: kernel 281 ms, user 2972687 ms. Process Utilization 99%%. System Idle 0%%. Interval: 3008473 ms.