Wow, a lot of discussion has taken place.
Upon those, I have to add this : The same problem (pale colors) had not happen on the same Laptop with Linux / Ubuntu 12.04 64bits: While using Ubuntu 12.04 and watching many UTube (flash) videos, I cannot remember a single video with that pale color problem.
So, as John VV stated, it might have something to do with .run installation, namely the NVIDIA-Linux-x86_64-295.53.run which was the file I used for installation.
anyway after all and I've disabled the HW acceleration in Flash settings it's become ok. I have tested it in 720p Flash videos and it plays fine.
But... the basic reason I always want Flash is not actually watching videos, as there are already html5 videos. But it's the ability of watching embedded videos, particularly the ones in Facebook. Has anyone noticed that, when one computer does not have Flash, it cannot show embedded videos in Facebook.