Gnomie Jon writes:

Hi, I’m Jon. I don’t know if you’ve heard of the "Ultimate Boot CD for Windows" (UBCD4Win), but it has saved me many times. It’s basically a Windows Live CD that you can use to fix your Windows computer. I’ve used it to fix my MBR, defrag, scan for viruses, wipe hard drives, and… well that’s about it, but it can be put onto a USB thumb drive.

The coolest thing is you get to pick what is on it. You don’t download the ISO — you build it! 😀 You get to pick your browsers, games, virus scanners, defraggers, and just about everything else. But don’t put too much on it or it will become a LiveDVD! I learned that the first time I used it. It can be found here.

By the way, I think it might be useful for people with Linux or Macs since it’s a "Windows Live CD" and they could use it to use Windows programs.