TDK DVD +RW 1-4x

I'we been writing lots of important data of mine onto these DVDs (because of format-reinstalling pc) with a PHILIPS DVD-RAM SDVD8821 using Nero xpress and i didn't werify the data or check if I can access it (I was burning some files on TDK DVD +R 1-16x also and they DO work). Now I can't get any data from those DVDs, because they are recognised as blank DVDs, but if I carefully look at the data side of the DVD I can see that there IS data on it. So pls suggest any software or any means to recover those files, I need them so badly.