Reader Vishal writes: I just got my hands on the new Office 2007. Before I install it I want to ask some compatibility questions. Would 2003 Office files from other PCs work on the 2007 Office PC? And will I be able to open the Office 2007 files in Office 2003 on my other PC?

Bottom line: Yes, you'll be able to open both types of files on both machines, but opening Office 2007 files with Office 2003 will take a little work on your end.

Microsoft changed the Office file format with version 2007, it says to "reduce file size, improve security and reliability, and enhance integration with external sources." Micrsosoft has tried to push these file formats, which it calls Open XML, to becoming an industry standard, but efforts to "fast track" its standard application have so far failed.

First let's look at the easy part of the equation: Office 2007 can open Office 2003 (and earlier, at least back to Office 97) files without any additional software. Just double-click and you're on your way.

To open Office 2007 files with earlier versions of Office, you will need to download and install the Office 2007 Compatibility Pack, which you can get here. The compatibility pack works with Office 2000, Office XP (aka Office 2002), and Office 2003. If you have an older version of Office you will not be able to open files saved in the Office 2007 native format; you'll have to save files in a different format in order to open them with, say, Office 97.

Before you install the compatibility pack, make sure your version of Office is completely up to date by running an Office update either through the Windows Update website or by clicking "Check for Updates" in the Help menu of any Office application. Don't skip this step! There's a relatively new Office 2003 service pack out that you will need first and which is not auto-installed by Windows Update.

I've used the compatibility pack extensively with Office 2003 and have had no problems with it. That's a good thing, because without it there's no way to open Office 2007 files at all.