If you dual boot between Windows NT and Windows 9x, you'll probably want to install your favourite applications under each operating system. The basic steps are easy: install applications under one OS on a partition that both OSs can read, then boot the other OS and install the apps again to the same location. You might run into a snag, though, if you use Microsoft's Outlook 98 e-mail and personal information manager program.

Outlook 98's problem is that it assumes you'll use it from within only one OS. I'd already been using Outlook 98 for several months on the Windows 98 side of my Win 98/NT dual-boot system when I finally got around to installing it under NT. To my surprise, Outlook had no clue that I already had a bulging in-box elsewhere on the hard disk. No matter where I looked in Outlook's settings ù even in the Windows NT Registry ù I found nothing that would let me point the program to the outlook.pst file on my Win 98 partition.

So I tried using brute force to copy the file to Outlook's seemingly static location in Windows NT (\WINNT\Profiles\user\Application Data\Microsoft\Outlook\, where user is my log-on name). After hours of tweaking, I came up with a killer batch file that copied outlook.pst from the Windows 98 partition to Windows NT's, launched Outlook, and then copied the file back again when I exited Outlook. Sadly, my 35MB outlook.pst file made the whole exercise cumbersome.

That's when I happened upon a simpler solution: if you delete outlook.pst from its default location (noted above), Outlook will ask you where to look for it. Navigate to the existing file's location (select Start-Find-Files or Folders to find it first), and then click OK. If you want to segregate data from applications (which is a smart idea), you can also use this trick to move your outlook.pst file to a separate data partition or folder.

If you've customised Outlook's Shortcut bar or created any mail rules, those settings are contained in two files that end with .fav and .rwz, respectively, in the directory that contains outlook.pst. The file-deletion trick doesn't work with these files, so you'll have to copy them from the Windows 9x location to the corresponding folder on the Windows NT partition. Lastly, if you have Outlook set to automatically archive old messages, they end up in the archive.pst file in the same folder. To ensure that all of your archived messages end up in one place, open Outlook under Win NT, select File-Archive, click Browse, and then navigate to archive.pst on the Win 9x partition and click OK. You may also have folder-level autoarchive settings. To point them to the correct archive.pst file, choose Tools-Options-Other and then click AutoArchive.