I bought 4.5 but had trouble with the program using the AT&T Natural voices, and Dragon Speaking Naturally so I uninstalled it. I downloaded the new version thinking maybe it would work better. So far so good! My OS is WinXP Pro and I have a AMD 2. processor with 1gig of ram. I also have a matrox video card with dual monitors. The program seems to operate fine even when I drag it to the other monitor. I did find some issues with the daily planner though. If you type " Meeting at Viktor's" it will tell you invaild time, no matter What time you put in.....but if you type " Meeting at Viktors" it seems to work. Also there were a few times that I put in a date and time in the AM and it did not show up on the calendar.....so I put it in again....still nothing, so I changed the time to PM and it took it! When I closed the program and opened it again, it read out the two missing meetings as well as the one with the PM time. I think I will stick with my "Talking Reminder" for my appointments till the bugs are worked out of this one. Maybe you guys could look at that program and get some ideas from it.
http://www.softwareriver.com/ It works GREAT but unfortunately it is only a calendar and has not the functions of Speach Recognition that Hal has. I am very impressed with the new characters. Though why the female characters are so nice in comparison to the male is beyond me. I chose Mike as he was the most realistic but he really is not very nice looking! Still he impresses everyone that comes into my office, especially when he talks and opens programs on command. I think they should redo Sam in his suit to be as realistic as Mike!

BTW here is the url of the AT&T Voices which beat the heck out of MS's!
http://www.naturalvoices.att.com/demos/