I posted it in the "cleaning up trash" thread. First uninstall nero if you already have it, and reinstall, but in the installation options, untick everything except startsmart, express, and burning rom. That makes the install take only 146 MB, and burning takes around 45-50 MB in memory. Not exactly lightweight, but compared to the highly bloated 1 gig install and 100 mb memory it takes regularly, its better like this. Since nero is one of the best burners feature-wise, I guess this one's better than others suggested here

Try it.