Why is Outlook 2007 crashing 4 times a day?

I’ve been having a recurring issue with MS OFFICE OUTLOOK 2007. I can’t work a day without OUTLOOK crashing completely, and usually it’s at least 4 times @ day. I’ve called the vendor from whom I bought the computer and program (since MS won’t support it), and they’re of no help. I’ve tried other support forums, to no avail. I need some help, or I’ve wasted $2,600 on what was supposed to be the best computer around. Please help!!!