oracle - ORA-12514 TNS:listener does not currently know of service requested in connect descriptor error -

i have windows server on virtual machine build 2 years ago. installed oracle database , sql server on it. worked fine. last 2 days try use oracle database , got error:

ora-12514 tns:listener not know of service requested in connect descriptor

i checked listener.ora , tnsnames.ora , couldn't found error.

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 = this_is_my_host_name_or_ip)(port = 1521))      )    )    default_service_listener = (xe)

and tnsnames.ora

main_database =    (description =      (address = (protocol = tcp)(host = this_is_my_host_name_or_ip)(port = 1521))      (connect_data =        (server = dedicated)        (service_name = xe)      )    )

ok. after build virtual machine , installed oracle database(xe) again still have same error. oraclexe , tnslistener services started. ideas?

please help.

well. found solution not best solution guess. oraclexe installed already. when changed name of virtual os(ex. computer name user-xxx , changed user-zzz) got error:

ora-12514 tns:listener not currently...

i saw listener.ora , tnsnames.ora , host was: host=user-xxx

i thought if i'll change user-xxx user-zzz , should work. tried restart system anyway didn't work.

solution simple. uninstall oraclexe , install again under new name. if know better solution please write.