I have a Denon DVD-1920

Question

I have a Denon DVD-1920 DVD/CD player that is less than 18 months old. It has developed a problem whereby it refuses to play any DVD through to completion. It will play for a short period of time and then either freeze or lose the picture completely. The instructions allude to the ability to clean the lens, but the manual is not particularly helpful as to how one should attempt or accomplish this task (eg. must the unit be disasembled to gain access?) Any and all assistance would be greatly appreciated. Thanks!