TechNibble no longer provides the USB Computer Repair Utility, but I use a program I've loved for a long time. Liberkey .com
It's developed by the French, but has an English version.
It's the ultimate USB Pocket Army Knife for Computer Tools.
Liiberkey philosophy is:
*It must be free
*Must run on a USB stick directly
*Liberkey will auto update all your applications on the USB key
The tools cover every topic you can think of. And you can customize what you want on it and even add your own tools manually.
I run GIMP, Open Office off it on computers that are not mine when I need to.
It has tons of securty related tools, cleaners, sys info, benchmarks, ftp, browsers, the list goes on and on.
It really is amazing and got me out of a bind many a time when I needed a tool I didn't think I had and I said "let me check my liberkey USB" and there was a program on there I didn't know I had that fixed the issue.
I have over 300 portable programs on it.