Or, alternately, if you have an external CD/DVD drive you can connect via USB, you can boot to a CD. If its an XP netbook, you can try a bartPE disk, or a linux disk such as Ubuntu (do not install, just boot to the disk itself.) Connect an external drive or flash drive, copy your files off, and do whatever you have to do.
Some netbooks have very hidden recovery partitions, so dont be to eager to just ru off and reinstall via a CD, or you'll lose it all.