Oracle 10g Express in Windows on USB key

Hey folks, I've been playing around with this for a bit, and having no luck.

If I run the Oracle XE installer, everything is fine, it works great. But I want one installation to work on several machines. Ideally I'd run it off a USB key mounted to a folder on C:.

Has anyone done this? I can assume I'll have Administrator privileges on all the computers I try this on. That way I can dynamically create the necessary Windows services. So I made a copy of all the files in /oraclexe to /oraclexetemp, exported the registry key for HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE, uninstalled the Oracle XE, copied the files in /oraclexetemp back to /oraclexe (so all the absolute paths are still correct), imported the registry key, recreated the services, and start up the services, which start up with no error. When I try to log in as SYSDBA with sqlplus.exe, I get a ORA-01033 error, "ORACLE initialization or shutdown in progress". I also changed the .ora files so that the host name was correct.

I plan to create a script that will do all this for me, but first I need to make Oracle XE work without being installed.

Can anyone help me? Thanks so much if you can