the oracle service would have gone crazy.
so, just create a new service using ORADIM
-- Delete the old service
ORADIM -DELETE -SID test -SRVC servicename

--Create a new services with the STARTMODE AUTO property
oradim -new -sid TEST -intpwd ORACLE -startmode AUTO -pfile C:orantadminTESTpfileinitTEST.ora

----------------------------------------------------------------------

then check the servicces in control panel ...
else
just write a batchscript with netstart!
if you use connect strings, make sure u start the listener too