I'm having trouble with NERO 7 essentials, please help

Back in March i bought the Sony DRX-830U, DVD/CD Rewritable Drive, in this purchase it also came a NERO cd titles NEro 7 Essentials…I’ve used this program along with DVD SHrink and am now having trouble burning. For some reason Nero does not want to burn anymore. After DVD SHrink is done processing Nero’s write speed is faded and i can’t seem to access it any longer. I think i have a OEM version? Does that mean i have a trial version and need to upgrade to the whole program to access it again. Can someone please direct me as to what i can do.