For Windows, if you've gotten that far, the services are running, otherwise you get an ora-12560 TNS error before seeing that particular error message. See the services applet, Start/Run/services.msc and there will be four or five oracle entries, only two matter for XE.Connected to an idle instance.
Unfortunately, it looks like the installer didn't get to finish all its setup tasks. It should create your database instance , start it up, set up the spfile, controlfile, datafiles, and so on.error in identifying file 'C:\oraclexe\app\oracle\product\11.2.0\server\dbs/spfileXE.ora'
net localgroup administrators ... Members Administrator <domain>\<user1> <user2> ... echo %USERNAME% ... ? user1? user2? if in a domain: echo %USERDOMAIN%