Program to draw anywhere on screen?

Question

I am looking for a program that will allow me to draw anywhere (in any program/on the desktop, etc.) with my mouse on the screen. The program should: - be free - allow me to select colors - be lightweight (installer can be on USB and I can install anywhere) - run on Windows XP - Windows 7 (definately Win 7)

Answer 1

I would suggest Krita. It's a free program quite similar in layout to Photoshop. The download is available on their website. It does have a bit of a tendency to lag, but for a free program, it's quite good.