New Instance for Existing Database -- 10gR2 under Win Server 2003 64-bit

I'm a Unix/Linux Oracle developer who needs to ask a Windows-oriented DBA question. For testing purposes, one of the guys in this shop wants a new instance that will access existing database files. Working from home late at night, he copied all the files (control files, DBFs, and everything) and then blew away the instance and installed a new one.