BartPE also comes with a number of useful plugin programs for tasks such as virus scanning and CD burning. The latter feature lets you boot into Windows and copy files to a CD.
When I tried it on a test system, it worked perfectly, enabling me to boot into Windows from a CD, access my network and copy files. However, it won't help if you haven't built the boot disc before your system fails because the program that builds the bootable CD runs in Windows. The best advice is to run it now before your PC fails and store the disc it builds in a safe place.