My htc touch reminders won't sound. The general alarm works but not the reminder alarms in the calendar, texts, e-mail, missed calls etc all sound, just not the calendar reminders

From what I have already experienced so far, some WM6 builds seem to be prone to have their notifications queue messed up.
Google for 'checknotifications_arm.cab', intall it on your device, and tap on 'Options > Settings...', tick both checkboxes there. Tap ok,' and 'Clear', at the top of the application's screen. Your notifications queue will be free of garbage, now.
Then, go to your Calendar application, choose a day which has the next events with notifications (reminders), Edit each one of them twice: one to delete the Reminder settings, and another one to reset them (you'll notice that at the 2nd edititing action for each event, the Reminder settings will be shown as they were, prior to their deletion - less work to be done!). This will set Calendar entries in the notifications queue.
Your reminders should work from now on.
Hope you are able to sort your problems out.
Cheers! Carlos