The number of readings of this post (in excess of 1700) suggests to me that many people are concerned about IE8.
You could well be right Roger.
I've just been trying some more experiments on the Vista machine.
1. Started with IE7 as the default browser and active content from CDs allowed; IE7 opened when the CD was inserted in the drive.
2. Reset the "active content from CDs" flag; IE7 still opened when the CD was inserted in the drive.
3. Reset default browser to Opera; Opera was opened when the CD was inserted in the drive.
4. Reset default browser back to IE7 with "active content from CDs" allowed; IE7 opened when the CD was inserted in the drive.
5. Installed IE8 and made sure that "active content from CDs" allowed; when the CD was inserted in the drive IE8 started to open but then closed without displaying the intro.htm file.
6. Opened Windows Explorer and double clicked the intro.htm file; IE8 opened correctly.
7. Closed IE8; double clicked autorun.exe in Windows Explorer; IE8 started to open but then closed without displaying the intro.htm file.
8. Tried to open autorun.exe by using the Start/Run route; IE8 started to open but then closed without displaying the intro.htm file.
9. Opened IE8 from the Taskbar and tried to open intro.htm from the CD using the File menu; IE8 would not open the file; tried to open another .htm file from the CD using the File menu; IE8 would not open the file.
10. Reset default browser to Opera; Opera was opened when the CD was inserted in the drive.
11. Reset default browser to IE8 and made sure that "active content from CDs" allowed; when the CD was inserted in the drive IE8 started to open but then closed without displaying the intro.htm file.
12. Uninstalled IE8, thus reverting to IE7 as default browser; IE7 opened when the CD was inserted in the drive.
13. Closed IE7 then opened it again from the Taskbar; tried to open intro.htm from the CD using the File menu; IE7 opened the file after insising on doing so in a separate window for security reasons.
Conclusion: More or less as before. IE8 works differently with autorun.exe (and, apparently, other files on CDs) from the way that other browsers work with the program.
It's disconcerting that IE8 should start and then stop without displaying some sort of error or warning message. Either IE8 or the OS (Vista) is obviously trapping what it considers is an abnormal condition. In those circumstances a message to the user should always be displayed.
Graham