Media Player wont open any files

[hjanice]

My Media Player has stopped playing any media files, I have a WD HD plugged into the media centre and have used it this way for 6 months and the HD works in my pc and I can open all the files but the media centre has started to not play them.

I can select the files and when I press play the media centre goes to an arrow like it is attempting to open the files and just sits there and will sit there and not open the files regardless of how long I wait for it to do it.

I had another WD media centre do this same thing  so I just brought another one as I thought it was unusable at the time

Any ideas  

[foetus]

Try Hard Reset on both devices - button on bottom of device (little black hole)

[hjanice]

Thankyou that has worked for now, I was unable to fidn the rest button on this model at first but now I know where it is