rms,
Spoke to loads of people on this issue, all of which are blaming the next person. Rang EA games (makers of CD) they advised the error was in a "codec" file. We couldn't locate the audio folder or the codec file, which was thought was the problem. Copied these files from my brother (who has same hardware and running XP), however this still did not work. My brother has earlier releases of game so loaded new expansion pack onto his computer and it works a treat.
This, therefore, makes the CD and game fine and I must conclude that it is a system or hardware. We went back and forth with acer and microsoft windows supports but we are none-the-wiser.
We then backed up all the files and did a system restore to an earlier date when the game was working fine, but this did not change anything. We even went to extreme measures by trying to restore the computer using the recovery disks (taking the computer back to the way it was when we first bought it) but even this did not work.
Any hints or suggestions - thank you for helping me thus far, and sorry it took me so long to get back to you.
Stella.