If safety is a real concern, pull the drive from the notebook and buy a 2.5" USB drive adapter (of the appropriate kind: SATA or IDE). Then hook it up to a working PC (kind of short of these at your house ) and copy the important files.

If you want to replace the Windows installation,then boot off the CD and agree that you want to install it on the existing partition. DON'T format it, just select it. If it says that it replace the existing Windows installation, say OK. It will then install Windows.

This will give you a generic copy of Windows and may not have things like the sound, video, network, wireless and other drivers. You will have to either get them off another manufacturer supplied CD or download them from the manufacturer's Web site. Also, many of your installed Windows programs will not work since the registry settings are gone. They will need to be re-installed. In this scenario, Windows is usually installed in \Windows0 directory and the old install is in \Windows.

(Some PC's like my Thinkpad have a copy of the operating system with drivers and original software on a separate hard drive partition. If you invoke the restore process using these, it formats the drive first, erasing everything, and then restores the disk to factory condition.)

Frankly the only difference between the above install and the back-it-all-up and reformat it install is that you don't have to copy the data files in the first case because they are still there. Personally, I would never do a Windows install without backing up the data to a separate drive anyway. Hence, I usually back it up and reformat and load a fresh of Windows.

Never forget that you are dealing with Windows and err on the side of safety.