You can install two or more versions of Office onto the same computer, so since you already have Office 2000, you could install Office 2003 in addition.

During the install of Office 2003 keep an eye on the options, and change the default location of where Office 2003 expects to install itself to some other location of your choice. If there is an option to 'remove' previous versions, de-select that option.

There's more detailed information and guidance here;
http://pubs.logicalexpressions.com/pub0009/LPMArticle.asp?ID=762

That should explain the procedure and possible pitfalls much better than I can, in particular licensing issues.

One thing I note from elsewhere, ( http://support.microsoft.com/kb/218861 ). You cannot have more than one version of Outlook installed. If you use Outlook, then you should be aware of this.

Read those carefully and see if they help.

Good luck.

Mark