I can't login to oracle system account - oracle

Question

I recently installed oracle 12c and can't access the system local generated connection. (Ora-01017 error) eventhough I know for a fact its correct because I changed the password. Anyway, someone else on stackoverflow redirected me to this https://iwikte.wordpress.com/2008/11/28/unlock-oracle-system-account/, and I don't know how to set up these environment variables. I need help. If it makes any difference i'm using windows 10.
If these environment variables are not set automatically, do it manually
(export ORACLE_HOME=/opt/oracle/VIS/db/tech_st/10.2.0
export ORACLE_SID=VIS
export PATH=$PATH:$HOME/bin:$ORACLE_HOME/bin)

Answer 1

Please first try without setting variables.
Please run SQLPlus as administrator and connect as sysdba without giving password. If your variables are set properly you can just type sqlplus in cmd if not please find SqlPlus in your programs. Then type:
conn / as sysdba
If that won't. Please go to your ORACLE HOME directory and edit %ORACLE_HOME%\network\admin\sqlnet.ora file and check if there is SQLNET.AUTHENTICATION_SERVICES = (NTS) if not NTS change to NTS and restart database. Then retry with conn / as sysdba
When connected you can just call:
alter user sys identified by YOUR_NEW_PASS; or for SYSTEM user alter user SYSTEM identified by YOUR_NEW_PASS account unlock; and login with new password.
By the way why do you need to log as SYSTEM? Not just sys as sysdba? Some comparison about system accounts.
The instruction you got is for linux. In Windows one set environmental variables like shown here

Answer 2

from oracle version 12.2.x users cannot login using case insensitive passwords, even though SEC_CASE_SENSITIVE_LOGON = FALSE if PASSWORD_VERSIONS of user is not 10g.
following sql should show the PASSWORD_VERSIONS for a user.
select USERNAME,ACCOUNT_STATUS,PASSWORD_VERSIONS from dba_users;
USERNAME ACCOUNT_STATUS PASSWORD_VERSIONS
--------------- -------------- -----------------
dummyuser OPEN 11G 12C
to make PASSWORD_VERSIONS compatible with 10g
add/modify line in sqlnet.ora of database to have SQLNET.ALLOWED_LOGON_VERSION_SERVER=8
restart database
change/expire password for existing user
new users created will also have same settings
after above steps PASSWORD_VERSIONS should be something like this
select USERNAME,ACCOUNT_STATUS,PASSWORD_VERSIONS from dba_users;
USERNAME ACCOUNT_STATUS PASSWORD_VERSIONS
--------------- -------------- -----------------
dummyuser OPEN 10G 11G 12C