Enviroment for Oracle_home& Path

About oracle XE and client for oracle

In my environment, there is client for oracle exists, so after i install oracle XE, there may problem happen.
after test for some cases, there two enviroment variables is very important.
Oracle_home(where is the configure location)
Path (where is the bin location)
some time you may be use tns_admin, this can change folder which configure oracle_home define.

when we use tnsping
there may question may be occur,such as
Message 3513 not found; product=NETWORK; facility=TNS  (file tnsnames.ora   can't be found)
TNS-12557: TNS:protocol adapter not loadable( there is no binary code)

for example:

Oracle_home:
C:\oraclexe\app\oracle\product\10.2.0\server

path:
C:\oraclexe\app\oracle\product\10.2.0\server\BIN;
C:\ORABASE\ORA11g\Bin;

Tns_admin:
C:\ORABASE\ORA11g\network\admin