Question : Problem: How can I repair install without losing settings?

SBS2003 - probably caught a virus.  They have a backup but they used an external device which just copied directories in drive c and d.  No system state backup. Starting tomorrow, they will start using the MS backup with system state.
Yetsrday the server was acting wierd, so they ran virus software.
When trying to boot, even in safe mode, there is an error about a bad password.  This is BEFORE logon screen.
I tried last known good config but same problem.  Password error or ??class.exe?? error
I can get to built in utilities partition, but cannot get a command prompt or even safe mode.
Is there a way to install the OS and not lose all the settings?  I have usb drive available, and a sata drive I could add to it if I need to.

Answer : Problem: How can I repair install without losing settings?

If you have your original Server 2003 CD you can boot to the CD, accept the license agreement, then when Windows examines your hard drive it should find the existing Server 2003 install on a partition and give you the option to repair it by pressing "R".