my music is showing on my phone but wont play

I have previosly purchased some albums and they have played ok. For some reason they no longer play any longer-when i select an album to play it seems to keep scrolling through the tunes but wont actually play any of them? (it is only some albums but not others??)

Any suggestions on how I can remedy this? My comuputer that had the backup on has been sent back to Dell as the hard drive failed (I will be buying a Mac next time!!) I do not wish to purchase them again and encounter the same problem- it is making me more inclined to buy the CD' and rip them in future.

Thanks

Steve