In addition to what CarlTR6 has suggested, I'd recommend another line of defense to solve system problems: creating a System Image. You can use the built-in Windows 7 utility (as well as creating the companion System Repair Disk), or a free product called Macrium Reflect that a lot of people recommend.
Backup Complete Computer - Create an Image Backup
Imaging with free Macrium
The system repair disk will easily fit on a single CD. But I'd suggest putting your system image on an external HD. Too many possibilities for problems if trying to image to DVDs.