Regularly files will disappear if MBR is damaged, to recover the date u just need a data recovery tool to scan and retrieve, it is the most convenient way. http://www.piriform.com/recuva
is Ok. But if it fails try this: http://www.freenew.net/windows/icare-data-recovery-software-45/68220.htm
It may takes a couple of times if the files are large.