Can you help on a strange problem?

Hi all,
Spent a long time yesterday downloading and installing various codecs including xvid and Divx ;-) amongst others to get some downloaded movies to work. Problem I now seem to have is that any WAV or MP?? files I now play are coming out slightly echoy and high pitched. As a result nothing sounds right. I tested a mid file and that plays OK but any mp3 or wav makes vocals sound like their on helium!!

Can you help???

Many thanks in advance folks... :D

[dubbs]

We'll looking through my movies to see if all are affected and one isn't. I've got one that's video encoded as Xvid and Audio encoding is described as "Unknown (tag2000)" I think this is AC-3. The other 2 movies I've checked with virtual dub are both running fraunhoffer iis mpeg3 codec.

Could this be the problem for my high pitch problem? If so can I edit the settings of the codec?

One other question... could that also affect my WAV playback which is experiencing similar problems....