Sharp Wizard OZ-590A Handheld

For fifteen years, I had a Sharp YO-600 electronic organizer.  It only had 64 KB of memory, so I reached the point where I had to get something with more memory.  Naively, I purchased a Sharp Wizard OZ-590A.  I can't begin to express how disappointed I have been.  When I turned the YO-600 on, I could select a function and see the information immediately.  There was a "secret" function which I could use for select information -- it didn't interfere with everyday activities.  On the OZ-590A, every selection (except calculator and calendar) must be preceded by my password.  What a pain!  I don't care if everyone knows that I have a dentist's appointment on January 21st at 3 PM, but I don't want anyone to know that my bank PIN is 4321!  If I want to "hide" my PIN, I have to "hide" my dentist's appointment.  On the YO-600, I only needed a password for information that I chose to keep secret.  When I chose the schedule function on the YO-600, the current date was displayed along with everything that was on my "to-do" list for that, or any previous, date, anything scheduled for that date, and anniversaries on that date.  On the OZ-590A, a list of every entry from that day forward is displayed. The date of the scheduled event is only visible if the event is selected, so the first entry may be for something next week, not today -- no anniversaries or "to-do" items are visible; those functions must be selected separately.  I like an organizer in which I can select a date and see everything that is happening, or needs to be done, on that date.  On the YO-600, "to-do" items were displayed until I deleted them.  For example, if I entered "Pay phone bill" in my "to-do" list for January 1st, it appeared on the schedule on January 1st.  If I didn't delete it, it would appear again on January 2nd and every successive day, preceded by an exclamation point.  Anniversaries (birthdays, etc.) would appear automatically every year without any intervention from me.  Not so on the 590A!  Once anniversaries are entered, I have to scroll through the entire list every time I want to find one, and the anniversaries must be entered with a year (Aren't anniversaries yearly occurences?).  There is no way to quickly see when an anniversary occurs.  The "to-do" list also must be accessed separately, and an item must be selected in order to see when it should be done.  If a "to-do" item was to be done on January 1st, it is hidden from view on January 2nd.  Only by scrolling up can one see that an item was to have been done in the past.  The YO-600 had a function for entering information for a period of time (for example, Christmas vacation from Dec. 20th - Jan. 4th), but the OZ-590A does not, so "Christmas vacation" must be individually entered every day during the period.  Need I go on?  I have had the OZ-590A for less than one year, and the display now has streaks which prevent me from reading the entries.  As I said initially, the Sharp Wizard OZ-590A is a terrible disappointment.  I don't understand why Sharp did not stay with its highly efficient YO-600.