if you have 1GB of RAM installed, then I expect the cpu wouldn't be limiting. On the other hand a system with a max RAM of 512MB might be suspect for the latest Flash Player.
In a virtual machine with single core cpu and 512MB RAM I can run flash video with sound all day long in either Chromium or firefox using Xorg or Xvesa and flash v11.2 With a little less memory Firefox will just barely run flash video but Flash in Chromium will not likely run at all.
if not a network problem, I believe a wipe and a re-install is next step. I have seen this exact problem before, but can not remember how I fixed it, neither can I duplicate it with any of my current systems. When the installation is suspect as the flash install is here, best not to keep chasing one's tail. Better bite the bullet because I'm of the opinion a fresh install done right is the most expeditious method to resolve this dilemma
edit: Wrong thread