Firstly: Oracle XE 11g sets password expiry by default. Quiet annoying...
So my system account was locked.
How to unlock that I did the following on the window command prompt:
set ORACLE_HOME= "ORACLE_PATH" (D:\OracleXe\app\oracle\product\11.2.0\server) in my case.
ALTER USER system ACCOUNT UNLOCK;
ALTER PROFILE DEFAULT LIMIT