This group is for the older versions of SBS.  You may get more response in
the SBS 2003 Newsgroup.

SBS public Newsgroups:

SBS 4.x: microsoft.public.backoffice.smallbiz
SBS 2000: microsoft.public.backoffice.smallbiz2000
SBS 2003: microsoft.public.windows.server.sbs

if your current news server does not carry these groups you should
be able to connect directly to news.microsoft.com

 Due to a server failure I tried starting up the server in safe mode, that
 didn't work. Next I used the original Windows install CD to do a re-install
 of Windows SBS 2003 R2 (not a full install).

 However, when I enter the login details of the Administrator in the logon
 screen, the folowing message is displayed: "A problem is preventing Windows
 from accurately checking the status of the licence for this computer. To
 proceed, your copy of Windows must be activated with Microsoft. Do you want
 to activate now?".

 If I click 'yes' I am redirected tot the login screen.

 If I click 'no' I am redirected to the login screen.

 If I click 'cancel' the computer shuts down.

 The above means that there seems to be no way to bypass this activation check.

 The strange thing is that the clients are able to login to the server.

 The http://support.microsoft.com/kb/310794/en-us solution on the Microsoft
 support site doesn't work since the following files aren't present:

 HKEY_USERS\.DEFAULT\Software\Microsoft\Cryptography\Providers
 HKEY_USERS\S-1-5-20\Software\Microsoft\Cryptography\Providers

 Hoping for a solution!