1. Oracle XE, unlike other versions of the database, uses a fixed SID (XE) so the installer only lets you set your SYS/SYSTEM password at install.
2. the white colored version was actually a deprecated application SQLPLUSW.EXE. if you google for sqlplusw.exe you will find many links discussing how to get it to work in 11g (not supported) or a range of alternative tools. for example SQLPLUSW.exe Not supplied with 11g