Rebuilt my test environment yesterday on Win2K8 R2 and when it came to installing CRM the installer refused to continue as the OS was not compatible. This despite my installing countless times on W2K8 R2 without any issues at all.
On further investigation it turned out that Win2K R2 SP1 (which came out last week 22nd Feb) was installed in the Updates. Will attempt removal tonight and see if this resolves the issue (don't see why not).
Thought you all ought to know. Would also be interesting to hear from anyone who updates to SP1 after the CRM environment is installed and running.
Cheers