My computer cannot seem to read DVD's. When I put them in to my disk drive (DVD rewriter) it comes up with a box saying 'blank disc' and gives me options like burn files to cd, as if there was nothing on it. When I go to My Computer and double click on the disk, or right click and explore, it lags a lot then freezes up until I remove the disk from the drive. The DVD's I am trying to use are DVD+R's. Any ideas?

have you tried cleaning the lens?

No, but it reads CD-R's fine. So I don't think it is the lense.