Outlook 2007 has disappeared

All of a sudden I can no longer open Outlook 2007 beta. It defaults to a
screen for setting up a hotmail account or for a dial up connection (I am on
Broadband). I have tried doing a repair from the disk with no luck and the
Outlook app. doesn't appear in the Office program file. I had this problem
once before and had to completely reinstall the 2003 version. I tried the
beta version again and has been working fine for about a month. All the
other beta programs seem to be working fine.