Invisible ISO Discs

Hi guys,

I have two laptops and a desktop PC. The two HP laptops (one running W7 Ultimate, the other W8RP) and neither can see iso files. I have some DVDs with ISO files which work perfectly on my desktop and also on other desktops but neither laptop will boot from them nor will they even recognise the DVD as a blank!

I have previously used the DVDs with the ISO files on the laptops without and problems, so why have they gone on strike

Come on guys, all minds together for any usefull suggestions.

Cheers

DD