The Ultimate Boot CD is a free old-school PC diagnostic and repair utility.
UBCD V5.2.6 is now available for download. Parted Magic has been updated to 2013_08_01. CPUstress has been updated to V2.3.5 (with thanks to Explorer09). The xfprot module within Parted Magic has also been updated to V2.4expl6 (again with thanks to Explorer09). The changelog is available here. You can download the latest version here.
See also:
Tutorials:USB Installation
YUMI-Install Ultimate Boot CD (UBCD) to a Flash Drive in Windows