to try since you mention no error messages, how you are trying to start it or any other info.
First, open your TaskManager and see if it is already running as a process - if it is se,ect it then click the "End Process" button then try to start it again.
If it isn't open a command prompt and enter the following command (substitute the actual path to your Outlook Executable if your path is different) -
"c:\Program Files\Microsoft Office\Office\Outlook.exe" /safe
My Outlook 2000 just won't start!!
What data recovery software do you recommend for this kind of trouble.