Resolving Oracle ORA-12853 error in Windows Server Environment during startup

I was getting the following ORA- error:

SQL> startup
ORA-12853: insufficient memory for PX buffers: current 0K, max needed 144K
ORA-04031: unable to allocate 21616 bytes of shared memory ("large pool","unknown object","large pool","PX msg pool")

Total server memory is 16GB