I would have to say one thing I do not like about Outlook is my PST file has gotten corrupt a few dozen times over that past decade. I know 10 years is a long time but still it's frustrating when it happens.
I will cover in a second a few free options you have to repair your Outlook account but before I do that you should be aware of a few strategies so it does not happen again. The first is to always backup your PST file onto an external hard drive or over a network to another location. You can use the free Personal Folders Backup add-in from Microsoft. This is a great way to ensure you are backing up your file in case of corruption
Chances are you found this article because you were looking for a way to recover from a bad PST file and you do not have a backup. Not to worry. If you have not already you should use the built in repair tool called scanpst.exe. The location will vary but if you do a search for scanpst.exe you will find it. Other wise you can browse to C:\Program Files\Common Files\System\Mapi\1033\. Like I said your location may be a little different but start following the above and you are sure to find it.
While this tool is free it will not always work. I have used it several times with great results and only a few time it was not able to fix my corrupt PST file. If it does not work for you and you need all those e-mails and contacts then you will most likely have to spend a hundred bucks on a good recovery program. I hope you do not have to do it but I have a program myself so I know how you feel.