Messed up Calendar/Task items & times

Somehow many of my calendar and tasks got screwed up, reminder times are wrong (ie. 3am), appts that now span 2 days, ect.

Ive cleaned up the tasks and appts, now I want to create a fresh outlook db on my pc to sync to.

Any quick suggestions on how I can delete my pc data, so that I can sync my 'fixed' calendar/task data to it? Can I just delete the .pst file and then open outlook, to create a new one?

Also, has anybody had any trouble with calendar or task dates/times or reminder settings, randomly changing like this? Its quite a mess.

Thanks.