While Windows 7 has its own DVD-CD burning program, it can be slow at times. In addition, it offers no capability for creating ISO images. These do.
ImageBurn
ImageBurn enables you to burn most types of DVD/CD images, including .iso, .nrg, .bin, .img and others. The program offers direct support for many of the latest CD/DVD writers. In addition to writing of images, you can also use the software to build your own ISO images from files and folders of your choice. ImgBurn includes a variety of advanced features to deal with dual layer DVDs, create DVD folder structures and more. Very capable, no documentation provided though.
You can get it here:
http://www.snapfiles.com/get/ImgBurn.html
BurnAware Free
BurnAware is a CD/DVD/BlueRay disc burning software that is designed to cater to your basic disc burning needs. You can create data discs for backup purposes, Audio CDs that can be played on any CD player as well as music discs with MP3 and WMA files to be played on a PC or compatible CD/DVD player. The program also supports burning and creation of standard disc images in .iso format. BurnAware Free does not support bootable discs, disc copying, a commercial version is available that offers those features. This program automatically installs the Ask.com toolbar unless you opt-out.
You can get it here:
http://www.snapfiles.com/get/burnawarefree.html