my oracle db won't open please help
ORA-600 errors are usually bad news. ORA-600 on OraFAQ.
If this is an environment you or anyone else cares about I recommend:
1) Opening an Oracle service request
2) Find your organizations DBA and engage them immediately
3) Dig those backups out because you may have a significant corruption of RDBMS binaries or data.  

Best of luck!