We generate CSV files from our web application and most people can
access them from Internet Explorer no problem (Excel starts within an
IE window).

However, some users in Denmark have reported that Excel does not load,
all that happens is that the IE window appears briefly then disappears.

I have done some testing and found that if I change my Regional
Settings to Danish, it fails in the same way. However, if I then reset
back to English, it still fails, even after a reboot.

These are the symptoms:-

1) When region is Danish, saving a CSV file locally and double-clicking
it within Windows Explorer causes Excel to start but puts all data into
a single column. I understand that as the list separator for the Danish
region is ";" and not ",".

2) If I create a HTM file locally that references the CSV file as a
link, this still works as above as long as I open the HTM file from
Windows Explorer (ie. it is not http but a file name instead)

3) If I then copy the HTM file and CSV file to a local Virtual
Directory and open the HTM file in Internet Explorer using
http://localhost/VirtDir/myTest.htm and then click the link, it fails
by quickly displaying a blank IE window and then closing.

I have ideas on how to lookup the users Region and set the correct
delimeter in the CSV file but have no idea why the file will not open
in Internet Explorer over HTTP. Even worse, I cannot get them to work
even when I revert to English so my PC is out of action for all CSV
files.

Any ideas please?