For your future reference.
Office Documents Open in Internet Explorer
When you click a Hypertext Markup Language (HTML) link to
a Microsoft Office file (such as a Microsoft Excel
document), Internet Explorer may open the file in Internet
Explorer, instead of opening the file in the appropriate
Office program.
http://support.microsoft.com/?kbid=162059 (Mar. 17, 2002)
In-Place Activation Using Internet Explorer 5 Does Not
Work for PowerPoint Slides
When you configure Internet Explorer to open Office files
in the appropriate Office program on a computer that is
running Windows NT 4.0, the in-place activation does not
occur when you open PowerPoint slide files.
http://support.microsoft.com/?kbid=290180 (i. e. 5. NT4
Oct. 18, 2002)
OFF2000: HTML File Opens in Another Office Program
For example, if you attempt to open a file by typing a URL
path similar to the following in the File name box of the
Open dialog box:
http://localhost/sample9/Default.htm and
click Open or press ENTER, the file opens in FrontPage
rather than Word.
http://support.microsoft.com/?kbid=220712 (Oct. 23, 2002)
WD2000: Web Page Opens in Different Microsoft Office
Program
http://support.microsoft.com/?kbid=224689 (Mar. 2, 2001)
Henri Leboeuf
http://www.generation.net/~hleboeuf/index.htm