oracle11g - Oracle 11g XE ORA-01034 and ORA-27101 after multiple installation of 10 and 11 versions -

1. windows 7 x64
2. local instance of oracle 11g xe

hello, i'm new oracle. have reinstalled oracle few times (version 10 , 11).

so i'm getting following problems after installation when try execute

sqlplus sys sysdba 

i ora-12638 , secod problem can't connect http://127.0.0.1:8080/apex/f?p=4950 (on previous installation of oracle 10g able connect it).

than fixed ora-12638 setting sqlnet.authentication_services= (none) in sqlnet.ora file.

after fix stoped , started database (oracleservicexe) after use sqlplus sys sysdba (ora-01031: insufficient privileges). i'm trying login system.

error: ora-01034: oracle not available ora-27101: shared memory realm not exist process id: 0 session id: 0 serial number: 0 

so i'm trying fix issue. found out few tips might related oracle_home , oracle_sid added environment variables following values

oracle_home = c:\oraclexe\app\oracle\product\11.2.0\server\ 

i checked (echo %oracle_home% returns c:\oraclexe\app\oracle\product\11.2.0\server)

also run command in terminal set oracle_sid=xe (and aslo checked returns xe) after restarted oracleservicexe , tried again login system, same ora errors (01034 , 27101)

1 - checked listener status

c:\>lsnrctl status  lsnrctl 64-bit windows: version 11.2.0.2.0 - production on 06-╩┬▓-2017 12:16 :16  copyright (c) 1991, 2014, oracle.  rights reserved.  connecting (description=(address=(protocol=ipc)(key=extproc1))) status of listener ------------------------ alias                     listener version                   tnslsnr 64-bit windows: version 11.2.0.2.0 - produ ction start date                06-╩┬▓-2017 11:36:35 uptime                    0 days 0 hr. 39 min. 43 sec trace level               off security                  on: local os authentication snmp                      off default service           xe listener parameter file   c:\oraclexe\app\oracle\product\11.2.0\server\network\a dmin\listener.ora listener log file         c:\oraclexe\app\oracle\diag\tnslsnr\iiaroshenko\listen er\alert\log.xml listening endpoints summary...   (description=(address=(protocol=ipc)(pipename=\\.\pipe\extproc1ipc)))   (description=(address=(protocol=tcp)(host=[iiaroshenko(host info)...])(port=15 21))) services summary... service "clrextproc" has 1 instance(s).   instance "clrextproc", status unknown, has 1 handler(s) service... service "plsextproc" has 1 instance(s).   instance "plsextproc", status unknown, has 1 handler(s) service... command completed 

2 - checked relevant services started restarted oracleservicexe & oraclexetnslistener

3 - checked path variable correct checked enviromental variables (i have oracle_home = c:\oraclexe\app\oracle\product\11.2.0\server\ , int path have c:\oraclexe\app\oracle\product\11.2.0\server\bin;

4 - tsnnames.ora , listener.ora are tsnnames.ora

xe =   (description =     (address = (protocol = tcp)(host = [iiaroshenko(host info)...])(port = 1521))     (connect_data =       (server = dedicated)       (service_name = xe)     )   )  extproc_connection_data =   (description =     (address_list =       (address = (protocol = ipc)(key = extproc1))     )     (connect_data =       (sid = plsextproc)       (presentation = ro)     )   )  oraclr_connection_data =    (description =      (address_list =        (address = (protocol = ipc)(key = extproc1))      )      (connect_data =        (sid = clrextproc)        (presentation = ro)      )    )  

listener.ora

sid_list_listener =   (sid_list =     (sid_desc =       (sid_name = plsextproc)       (oracle_home = c:\oraclexe\app\oracle\product\11.2.0\server)       (program = extproc)     )     (sid_desc =       (sid_name = clrextproc)       (oracle_home = c:\oraclexe\app\oracle\product\11.2.0\server)       (program = extproc)     )   )  listener =   (description_list =     (description =       (address = (protocol = ipc)(key = extproc1))       (address = (protocol = tcp)(host = [iiaroshenko(host info)...])(port = 1521))     )   )  default_service_listener = (xe) 

5 - checked oracle_home , oracle_sid in registry

hkey_local_machine\software\oracle\key_xe oracle_sid=xe oracle_home=c:\oraclexe\app\oracle\product\11.2.0\server oracle_base=c:\oraclexe\app\oracle 

6 - tried starting instance

c:\>sqlplus  sql*plus: release 11.2.0.2.0 production on ╫Є. ╩т│ 6 12:42:09 2017  copyright (c) 1982, 2014, oracle.  rights reserved.  enter user-name: system enter password: error: ora-01034: oracle not available ora-27101: shared memory realm not exist process id: 0 session id: 0 serial number: 0   enter user-name: 

7. in alert folder c:\oraclexe\app\oracle\diag\tnslsnr\iiaroshenko\listener\alert got few warnings "warning: subscription node down event still pending". have alert folder. (i don't have log corresponing oracle 11g xe - sudden ora-01034: oracle not available , ora-27101: shared memory realm not exist part 8)

so i'm confused this. succesfully installed oracle @ home, think issue might related installing , unistalling oracle 10 , 11 multiple times , might http://127.0.0.1:8080/apex/f?p=4950 not started.

i tried provide information accoring oracle 11g xe - sudden ora-01034: oracle not available , ora-27101: shared memory realm not exist . , if needed please tell me. didn't manage find database log tried @ $oracle_base/diag there tnslsnr folder in , no rdbms folder. time , patience).

my colleage helped me issue. solution unistall oracle, create new user , grant him administrative rights(computer -> manage -> local users , groups -> users -> add user). login user (.\user) , install oracle, after enter own account. after started page started work. i'm not familiar oracle, read issue more, hope solution someone.