There is a now a stand-alone executable for the O2 Platform (20Mbs) which has all the main dependencies and comes in 1 exe.
You can download it from: http://tiny.cc/O2Platform
Let me know if you have any issues running it
Note that this is not an installer, this exe file has all dependencies embedded and will extract them on first run.
You can put it on any folder (not the desktop since you will get a number of O2 folders in there :) ) or drive, and it should just run