Just install a version of the client
1, open. Start - Program - Oracle - OraHome92 - Configuration and Migration Tools - Net Configuration Assistant
2, select the "naming configuration" - the next step - check the "local", "host name", "Oracle Names" - Next
3, confirmed OK.
Installed two versions of the client to open PLSQL, prompted to enter user name password is canceled, so the main interface into the PLSQL Developer,
Menu Tools-Preferences, the settings window, select the Oracle-Connection, the corresponding settings window, locate the Oracle Home, select OraHome92, save the settings,
And then restart the PLSQL Developer, then you can normally logged.