BACKING IT UP

Microsoft Outlook the PIM (Personal Information Manager).

As good as Outlook is, it lacks any viable system for backing up your valuable Outlook information. Here's what you need to know about backup for Outlook. Outlook stores information in a data file called a "personal folder" file. It has a .pst extension.

If you use Outlook 97, your .pst file is stored in the Windows folder.

If you use Outlook 2000, that file is saved in the Windows\Local Setting\Application Data\Microsoft\Outlook folder.

Local Settings is normally a hidden file, so to find it using Explorer, you may have to select View from either Windows Explorer or My Computer and then select Folder Options. Click on the View tab and then click in the circle to the left of "Show all files" located below the "Hidden files" section. Click OK and close the Explorer or My Computer window.

The easiest way to back up all of your Outlook information is to copy your .pst file (in most cases Outlook.pst) to a Zip drive or to another hard drive if you have two drives.

From Windows Explorer, drill down to your .pst file, right- click on the file and then select Copy. Now you can go to the drive where you want to place a copy of the .pst file. When the drive is highlighted, click on Edit and then select Paste.

Outlook lets you archive your data to a file called "Archive.pst" which places your oldest data into that file. You can, from Outlook, click on Tools and then on Options. Select the Other tab and click on the AutoArchive button. Now you can set your Outlook program to automate the Archive process so that the process runs every so many days.

Finally, you can use Outlook's Import/Export feature to back up your data.

The Export feature copies data intact to a file, while Archive copies only old data to a file.

 To Export, open Outlook and click on file. Select Import and Export. The Import and Export Wizard will start. Select "Export to a file" and click on Next. Now select "Personal Folder File (.pst)". Click Next. Now select "Personal Folders" at the top of the dialog box to back up all of your Outlook data. Make sure that the check box labeled "Include subfolders" is checked. Click on Next. Select a destination for the folder. Outlook labels the backup file "backup.pst", and you can set the destination by placing the drive letter before the destination file name. For example, if your Zip drive is drive E:, you would just type "E:\backup.pst" (without the quotes). It's a good idea to select "Do not export duplicate items " in the Options box. Finally, click on Finish and your Outlook data will be exported.
 The nice thing about using Export is that you can choose to export any of the individual Outlook folders to export from. This lets you effectively back up just your Calendar folder or just your Contacts folder.

More detail on backing up Outlook here=> http://support.microsoft.com/default.aspx?scid=kb;en-us;Q196492
And Here => http://office.microsoft.com/downloads/2002/pfbackup.aspx

Outlook data is usually stored at the following paths:

C:\Documents and Settings\User Name\Application Data\Microsoft\Outlook\
C:\Documents and Settings\User Name\Local Settings\Application Data\Microsoft\Outlook\
C:\Documents and Settings\All Users\Application Data\Microsoft\Outlook\
C:\Windows\Application Data\Microsoft\Outlook\
C:\Windows\

You’d want to find and backup .pst files (Personal Folders) and the .pab file (Personal Address 
Book).

PST file corruption
When things go terribly wrong!

PST file corruption can be an all-too-frequent occurrence. Such was the case for many people who suffered such a corruption when upgrading from Windows NT to Windows 2000. Why do Outlook PST files corrupt when switching from NT 4.0 to 2000 on workstations, and is there a patch to fix this problem?

While I’ve personally never encountered the corruption issue while trying to upgrade, I’ve seen plenty of other cases of PST file corruption. When this happens, the Inbox Repair Tool and the Oversized PST And OST Crop Utility can help. Here's how.

Always make a backup
To address this specific migration issue, I would recommend the trying in WinNT to export to a file and then import in Win2000. Your PST files could become corrupted after an upgrade, so back up the files prior to upgrading. Another option is to rename the PST files to something other than Filename.pst, and then rename them back to their original names after the upgrade.

Of course, this solution only prevents future corruption; it doesn’t correct the corruption that’s already occurred. There are other solutions for this problem.

Using the Inbox Repair Tool
To fix corrupted PST files, you can use the Inbox Repair Tool. However, the tool isn’t always able to repair every PST file. It works by repairing the PST file’s header and then deleting anything in the file that it doesn’t understand. So if a PST file’s header is damaged, as may be the case for corruption that occurs during a version upgrade, the tool should have no trouble making the repair. But if the data within the file is corrupt, the Inbox Repair Tool will likely destroy what’s left of the file. That's why it's always good to make a backup of the PST file before running the Inbox Repair Tool.

The Inbox Repair Tool is located in the C:\Program Files\Common Files\System\Mapi\1033\NT directory of any system that’s running Windows 2000 or Windows XP. The tool’s filename is Scanpst.exe. Other versions of Windows also include the Inbox Repair Tool, but the tool’s location varies among these earlier versions.

Using the Oversized PST And OST Crop Utility
Another possible cause of corruption is that a PST file, prior to Outlook 2003, has a 2-GB size limit. Once this limit is exceeded, corruption occurs instantly. You can’t initially fix this problem with the Inbox Repair Tool. Instead, you’ll have to use the Oversized PST And OST Crop Utility first, and then follow up with the Inbox Repair Tool. The crop utility works by deleting about 25 MB of data from the file to bring the file back within specs. Use this tool as a last resort, because you can't control what data you lose when using it.
Oversized PST And OST Crop Utility Here
 You can get more detailed information from Microsoft by reading these Knowledge Base articles: Q197315  and Q296088 

Outlook did indeed have a limit of 2 GB on PST files in versions prior to Outlook 2003. Newer versions of Outlook (2003 and 2007) use a different default file format (Unicode). PST files in Unicode format can be up to twenty (20) GB. For more info, see KB article 830336 HERE