Did OL open before?
What updates did you do? Win 7, office?
I would suggest re-installing Office. Takes about 15 minutes, maybe less. You can uninstall from the Add/Remove Programmes in Control Panel, then fresh re-install, or re-install over the top.
To save any Mail/Contact/Calendar info; make a copy of your .PST file. Normally in C
Users\yourname\Documents\Outlook files. When you have reinstalled Office, simply import the .pst into OL.
Have to hand your ISP account details to setup your email account. You do have them written down, don't you?
If not, google your ISP, that will tell you the technical stuff that you need to enter. Incoming mail server, outgoing mail server.
So all you need is your email address, user name and password.