Joel,

Angela's suggestion is worth a go.  It should work if your 6.5 data and log files were separate, and if there's been no increasing of either file (this is done manually in 6.5) since the original creation.  Even if there has been increases - addition of new segments - then it may still work, but consistency errors will eventually find their way into your database.  So, if all goes ok I suggest BCPing out all your data and rebuilding the database anew.

If the suggestion doesn't work, it may be worthwhile going back to that old copy of master.  It's possible that your user database size has been static for some time and that copy of master still has some good info.