The best free tool I’ve found for Windows is Ultimate Boot CD. There is also one for Linux. It boots a live Windows environment using Bart PE, and is jam packed with every PC tool/diagnostic tool you could ever imagine. You have to download the .exe package and it creates the live CD from there. You will need a Windows install disk so it can pull files from it to create the live CD. You can also click the “plugins” button before creating the CD to download and add additional tools/apps.