Nope. It works on data black corruption. With hardware failure you need a backup - no questions about that.

I am curious though: the error message you posted:

ORA-01157: cannot identify/lock data file 1 - see DBWR trace file
ORA-01110: data file 1: 'D:\KELLER\KELLER\SYSTEM01.DBF'

1) Oracle can't find the file or something else was locking it.
Look for the drive and directory. Was it renamed? is it there?

2) Guess this is Windows NT/2000 so look in the Task Manager and check to see if Oracle.exe is running and if it is kill the process or reboot.

what does the dbwr trace file say?