Vista - windows mail freezes locking system

Sometime recently I noticed that the windows mail is freezing whenever I bring it up, locking the system.

This was not true when I first brought up the system a month or two back.

I have read that Windows cannot handle a large address book. I imported my old one and am now trying to delete unnecessary addresses. But having said that, my old address book does fine on XP. could it be that the conversion to the new causes problems that would not exist if the address book had been keyed into Vista?

Does anyone know of tuning practices that can be done to optimize the system? For a 2 month old system its seeming very doggy and slow. Does Microsoft have any idea of the problem and any solutions that anyone is aware of.

I have to say that I am not good at debugging and repairing system level problems like this. I know how to access the event viewer; but am stuck when it shows that a problem exists. Can anyone offer assistance in this area as far as who/where to turn to for help?

Thanks for your help,

Steve