My Bits and Bytes.

Think of situation when you forget you windows administrator password , you are stuck ! you can try following to get into the windows boot your system in Dos mode and rename SAM file under C:\WINDOWS\system32\config . and restart the computer when prompted use no password and press ENTER . if your partition are NTFS you might need to put your had disk on another computer and try steps above

Microsoft windows has inbuilt backup utility to backup your files to safeguard from computer crash , Hard disk crash or virus attack , link below describes windows backup utility in detail http://www.microsoft.com/windowsxp/using/setup/learnmore/bott_03july14.mspx