Win2k3 repair & version differences

I had a client w/ a Windows 2003 server that supposidly failed to come back up after installing Windows Updates.  The only reason it was W2k3 is because thier accounting software isn't (or wasn't at that time) compatable w/ 64-bit or 2008.  The machine would post, and as soon as it would start windows it would go to a black screen, and the hard drive lights would stop.  Even in Safe-Mode the result was the same.  The server had a COA for W2k8, the customer told me it was W2k3 standard, and gave me a Dell OEM W2k3 standard disk.  After a bunch of trouble shooting, it was time to do a repair install.  I booted the machine up off of that CD, and the install took off, no prompts or anything, it just installed it!  What it had done is do a parellel install of Windows!  It apparently saw the damaged copy, and just ignored it, didn't ask to repair it, and just installed itself on the d-drive!  Fast forward a few hours, I had reason to believe that this might be an Enterprise or R2 version of windows; after loading the registry hive from failed copy I was able to find out it was actually R2 Standard!