PS knowing abourt scanpst.exe and your event viewer is not an IT thing, it's
part of having a computer. Whatever you don't know about, find a newsgroup
for it and just ask.

Scanpst.exe will scan your PST file for errors and repair them. Close
Outlook. Do a file/folder search for scanpst.exe. Double-click it and follow
the prompts, which will include browsing to your PST file so make sure you
know where it is.

You may have to unhide hidden files and folders plus enable the view of
known file extensions to complete this.

Run scanpst.exe against your PST file with Outlook closed. If it finds
errors, when it's completed, run it again. When it completes a scan without
finding any errors, open Outlook again. Let me know what happens then.

Event Viewer: Right-click on My Computer and scroll to Manage. You'll see
the Event Viewer in the list of items. Expand it to find the Application
Event Viewer. Look for red error marks that are related to Microsoft Office.
If you find any, post the EventID number and source.