Cannot start SQL SERVER SERVICE in Windows Server 2000
You don't mention the version of SQL Server you are running, however, are you up-to-date with updates?  There have been fixes for Access Violations in SQL Server that you may not have at this time.

Here is an MSDN post that has some relevance (though it is specific to SQL 2008):
sql server 2008 is terminating because of fatal exception c0000005

Access Violations occur because the application has attempted to access memory areas that it doesn't own.  That is a problem with code.  And quite often there are service packs or updates that address these issues.

Without knowing exactly which version of SQL Server you are running a more specific fix cannot be suggested.