How do you use the "inbox repair tool"?
With Outlook closed, run the program named SCANPST.EXE. That's the Inbox
Repair Tool. It will ask you to browse to your PST and select it. Do that.
It will scan it for errors and, if any are found, will repair them but
making a second copy of your PST. It won't modify the original. You don't
have to copy your PST anywhere, despite what Sajjad said.