first make sure u have the inittest.ora in the directory.
then check the parameters in inittest.ora
all the parameters should that are quoted should be properly closed and the use windows notations for slashes.

usually there should be more parameters in the inittest.ora
and atleast 3 control files by default.

so, did u create the database?
or just installed the software?

if you have created the database, there should be more entries in inittest.ora

any how,
login as sys
and try to start database by giving complete path of pfile.

startup nomount pfile=' complete_pathinittest.ora';

right click on  my computer in windows.
goto properteries , select advanced tab.
there would be an otpion to set the environment variables.
set the ORACLE_HOME,ORACLE_SID there.
add ORACLE_HOME  to path.
with OEM, are u using OMS or just stand alone console?
for OMS did u istall repository etc?
for standalone, first you need to a tnsstring.
add entries in tnsnames.ora to connect to the local test dataase.
use that string to connect to database.
inside OEM, ther will an option to add database to  tree.
if you select them, your tns entries appear.
always, create a dba account for general database administration use it.
preferbly dont use sys account as it is meant for more powerful options