Recently I noticed disparity of colours on an image displayed on my Photoshop and Firefox. I remember a month back that my Vista created a new user profile for me as my old one corrupted. As a result my Lightroom and Photoshop custom profile was reset, all my Firefox browser bookmarks gone and a lot more similar things happened on some other programs.
So for Firefox in particular, I had to re-enable color management by doing these steps:
1-on your Firefox browser, type "about:config"
2-it will give you a "here be dragons" warning...don't be scared, just go in
3-in the filter search box type "gfx.color_management.enabled" and once the same line appeared in the list below, double-click until it shows its value set at "true"
4-you are done, restart your Firefox browser. now to test, compare if an image uploaded in your Flicker for example shows exactly the same in colour terms as when that image is opened in your Photoshop or Lightroom. they should be identical.