To repair your PST file, you’ll have to open the Scanpst.exe utility that’s included by default with Outlook. The only problem is that there’s no shortcut to it, so you’ll have to find it in the Outlook folder.

Open up explorer and then browse down to the following folder for Outlook 2007:

C:\Program Files\Microsoft Office\Office12

Or one of these folders for Outlook 2003 and earlier:

C:\Program Files\Common Files\System\Mapi\1033
C:\Program Files\Common Files\System\MSMAPI\1033

Once you open up the utility, you’ll have to find the location of your PST file by clicking the Browse button.
It will take a while to scan the file, and you’ll get a report at the end telling you whether you have errors in the file.

Click on the Repair button, and after a while you’ll finally get the “Repair complete” message.
If you are curious what was actually repaired during the process, you’ll find a text file in the same directory as your PST file with the same name as the PST file.

Here’s the scoop:

1. In Outlook, on the File menu, click Import and Export.
2. Click Export to a file, and then click Next.
3. Click Comma Separated Values (Windows), and then click Next.
4. In the folder list, click the Contacts folder, and then click Next.
5. Browse to the folder where you want to save the contacts as a .csv file.
6. Type a name for the exported file, and then click OK.
7. Click Next.
8. Click Finish.

That gives you a comma separate list of your Outlook Contacts. Transfer that to your new computer, then you can import them into your new version of Outlook with the following steps:

1. On the File menu, click Import and Export.
2. Click Import from another program or file, and then click Next.
3. In the list, click Comma Separated Values (Windows), and then click Next.
4. Click Browse, locate your file, and then click Next.
5. Click your Contacts folder or another folder that contains contacts, and then click Next.
6. In the list, click the file that contains your address list, and then click Map Custom Fields.

If those steps are too complicated for you, here’s the hint, just copy personal folder file from your old place into the new one.
Usually it was stored inside this folder:
C:\Documents and Settings\Administrator\Local Settings\Application Data\Microsoft\Outlook\xxx.pst
While for outlook express it was stored in:
C:\Documents and Settings\Administrator\Application Data\Microsoft\Address Book\xxx.wab