[dba-SQLServer]Restoring SQL Backups

If and when I get SQL Server running again (I'm about to re-install it after
going back to Win2KSP3), how do I get the backup files back in to SQL
Server.  It looks like SQL Server keeps the location and names of the files
inside the database or something.  IOW, there's no "browse for file"
function that I can find.  I have the data out in files on my disk (with NO
extension!!!) so I need SQL Server to ask me where to go to find these
things, display a list of the backup files, and then get the data back into
a new database.

Alternately, assuming my last failed installed didn't trash it, I need the
INSTALL to find and use the existing database that still exists on another
directory out on my D: drive.

Someone please tell me I haven't lost all my billing data.  I'm beginning to
panic here.

John W. Colby
www.colbyconsulting.com