This is a quick how-to guide for creating an Ultimate Boot CD 5 (UBCD5) boot disc.
Every tech should have a copy of UBCD5 in their toolkit.

Make sure that you have enough free disk space for the UBCD5 .iso (≈600MB)

Go to http://ubcd.sourceforge.net/download.html
*Do NOT click on any buttons that say Download or Download Free Now!*
(You won't see these if you are running an adblocker)

Scroll down to the "Mirror Sites" section
Click on one of the download buttons download.gifnext to ISO
Save the ubcd5##.iso file to your computer

After the download completes, you'll need to burn the ubcd5##.iso to a CD as an IMAGE:
If you have Windows 7 or higher, follow these instructions:
How To Burn an ISO Image In Windows 7

If you don't see the "Burn disc image" option, it’s probably because .iso is associated with another program.
Fix: “Burn Disc Image” Option Missing From Context Menu

Otherwise, you can download ISORecorder and follow the instructions here:
How can I write (burn) ISO files to CD or DVD?

To create a bootable flash drive, read Post#2