Bart PE
BartPE (Bart's Preinstalled Environment) is a lightweight variant of the 32-bit version of Microsoft Windows XP or Windows Server 2003, similar to Windows Preinstallation Environment, which can be run from a Live CD or Live USB drive.
A BartPE system image is created using PE Builder, a freeware program created by Bart Lagerweij. It requires a legal copy of Windows XP or Windows Server 2003. Additional applications can be included in the image using plugins.
As it often resides on a Live CD or USB drive, BartPE allows a user to boot Windows, even if a hardware or software fault has disabled the installed operating system(s) on the internal hard drive — for instance, to recover files. It can also be used to scan for and remove rootkits, viruses and spyware (that have infected boot files), or to reset a lost administrator password.
Read more about Bart PE: PE Builder, Description