Im sorry if this is asked before but Im in a desperate need of help!

I've recorded my videos into four DVD-RW disc. Now, I want to transfer them all into the computer. But once I put it into my comp's DVD drive, it doesnt pick up anything! the drive says that the disc is empty! I tried to connect using my camcorder but to no avail...

I can view the videos I took using my camcorder tho..

Im using a Panasonic VDR-D310..

I need help from you guys... I need to know what esle can I do to take the videos out from the DVD into my comp so that I could save the videos.. thx!