SQL> startup pfile=C:\oraclexe\app\oracle\product\10.2.0\server\database\initXE.ora
ORA-44412: XE edition memory parameter invalid or not specified
ORA-01078: failure in processing system parameters
SQL>


This is two parameter in initXE.ora that is changed according to your instruction.

*.sga_max_size=1048576000
*.sga_target=1048576000