We have a series of educational CD-ROMs on the market, which have been working OK on PCs and Macs for several years but are now manifesting major audio problems when played on Windows XP/2000.

Each CD comprises about 100 SWFs, Mac and PC projectors, and an autorun file. The SWFs range in size from 5-500 Kb, but most are around 200 Kb. They were built with Flash 3,4 and 5, but we have also produced an MX version, for testing purposes, and it is no better than the others. The program runs from the CD - no files are installed on the hard drive.

The original CDs were authored on Macs, but we have also tried re-exporting all files from a version of MX installed on an XP machine.

When the CD is played on an XP or Win2K machine, it goes through 3-6 SWFs without any problem, then the sound starts stuttering rapidly for a second or two before dying completely. Everything else (animation, interaction, etc.) continues to work OK, but there is no sound. The only way to restore the audio is to restart the application.

We have experimented with the following alternatives:

1. View SWFs on CD through Internet Explorer rather than projector. No improvement.
2. Copy entire CD contents onto hard drive and run from there. This increases the number of SWFs that can be played, but the problem still occurs.
3. Copy SWFs onto hard drive and view through IE. Same result as 2.
4. View SWFs through IE across the internet. Strangely enough, this seems to work OK, though it is obviously much slower. The only difference between the SWFs on the website and those on the CD is that the website ones have loading animations at the start.
5. Copy the web SWFs (with loading animations) onto hard drive and view through IE. This is relatively stable, but is a very clunky workaround.

We have tried both MP3 compression and Flash's own compression, but it makes no difference. We have also tried installing every Windows Update available and tweaking every XP system configuration imaginable, to no avail.

Interestingly, the audio always seems to fail at the beginning of a SWF - never halfway through it. When it does so, CPU usage rises to over 20 percent and stays there, even if the SWF is idle.

This is a mjor problem for us. We have spent weeks trying to resolve it and are getting absolutely nowhere. Microsoft (naturally) are not interested, and we are still waiting to hear back from Macromedia technical support.

Any suggestions would be greatly appreciated.

Many thanks

Andrew Campbell