Thanks for your reply. Just an update on this. Last night I opened the control panel and went into sounds, straight away I got a pop-up message saying that some settings had been changed and did I want to restore them back, so I clicked ok. Went back into WMP and the files play ok now.
Tried a DVD this morning and that works a treat too. So looks like it's all sorted now.
Thanks. Lee.
-------------------- Acer Aspire running Vista Home Premium