Oracle 7.0NT-Optimizer, full of bugs?

 Is anyone out there running Oracle on NT? I urgently need to hear about any problems you've run into, especially problems concerning the optimizer.

 I'm having serious problems getting it to make just about any smart decisions. I have a hierarcy of three tables with: 79 entries on the first level,
on the second level there's one entry for each day of seven years for every entry on the first level and on the third level there are 24 entries for each entry on the second level .
(:-?) (I hope you understand all the gibberish :-) )  I.e, 79 rows in the first table, 202 003 rows in the second and 4 848 072 rows in the third table. There are primary keys and foreign keys where apropriate.
 I have calculated statistics with analyze on all tables.

 The optimizer often refuses to use the indexes and instead executes a full table scan on the HUGE table! And yes, I am using the leading portion of the index, or even all of it with equal-sign pointing at an existing entry.  Sometimes the optimizer will use or not use the index depending of what range of dates I'm using in the query rather than the size of the date range.

I've been told that there is a bug preventing you from giving hints to the optimizer so that won't help either.

The Box:
System configuration:
PC i486DX2/66 32Mbyte

Disks:	C:[DOS-FAT] ~235M	DOS
			Windows 3.1
			Windows NT 3.1 Build 528
			Oracle Server NT ver 7.0.15.4.0 PL/SQL 2.0.17.0.1

PLEASE HELP.... Hans Lindberg Tel: 031-183151 EMail d7hansl_at_dtek.chalmers.se

    /      /    /	"-Fashion is a form of ugliness so intolerable
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